The Berkeley DB Java Edition Package: BDB JE Library Version 12.2.7.5 (Release 7.5.11) Change Log

Oracle Berkeley DB Java Edition 12c R2 Change Log

Release 7.5.11

Upgrading from JE 7.4 or earlier

In JE 7.5 the on-disk file format moved to 15. The file format change is forward compatible in that JE files created with earlier releases can be read when opened with JE 7.5 or later. The change is not backward compatible in that files created with JE 7.5 or later cannot be read by earlier releases. After an existing environment is opened read/write using JE 7.5, the environment can no longer be read by earlier releases.

Upgrading from JE 7.3 or earlier

No file format changes were included in JE 7.4 and there are no file format compatibility issues when upgrading from JE 7.3.

Upgrading from JE 7.2 or earlier

In JE 7.3 the on-disk file format moved to 14. The file format change is forward compatible in that JE files created with earlier releases can be read when opened with JE 7.3 or later. The change is not backward compatible in that files created with JE 7.3 or later cannot be read by earlier releases. After an existing environment is opened read/write using JE 7.3, the environment can no longer be read by earlier releases.

Upgrading from JE 7.1 or earlier

No file format changes were included in JE 7.2 and there are no file format compatibility issues when upgrading from JE 7.1.

Upgrading from JE 7.0 or earlier

In JE 7.1 the on-disk file format moved to 13. The file format change is forward compatible in that JE files created with earlier releases can be read when opened with JE 7.1 or later. The change is not backward compatible in that files created with JE 7.1 or later cannot be read by earlier releases. After an existing environment is opened read/write using JE 7.1, the environment can no longer be read by earlier releases.

In JE 7.1 the HA wire format also changed in order to support the durable transaction commits feature (see [#25057]). Until all nodes in a replication group have been upgraded to JE 7.1, this optimization is not fully applied.

Upgrading from JE 6.4 or earlier

In JE 7.0 the on-disk file format moved to 12. The file format change is forward compatible in that JE files created with earlier releases can be read when opened with JE 7.0 or later. The change is not backward compatible in that files created with JE 7.0 or later cannot be read by earlier releases. After an existing environment is opened read/write using JE 7.0, the environment can no longer be read by earlier releases.

In JE 7.0 the HA wire format also changed in order to support the TTL feature. Until all nodes in a replication group have been upgraded to JE 7.0, the TTL feature cannot be used. An exception will be thrown if a write with a non-zero TTL is attempted, and not all nodes have been upgraded. See further below for a description of the TTL feature.

Upgrading from JE 6.3 or earlier

No file format changes were included in JE 6.4 and there are no file format compatibility issues when upgrading from JE 6.3.

A behavior change was made to DiskOrderedCursor that may require some applications to increase the JE cache size. To prevent applications from having to reserve memory in the Java heap for the DiskOrderedCursor, memory used by the DiskOrderedCursor is now subtracted from the JE cache budget. The maximum amount of such memory is specified, as before, using DiskOrderedCursorConfig.setInternalMemoryLimit. [#24291]

Upgrading from JE 6.2 or earlier

In JE 6.3 the on-disk file format moved to 11. The file format change is forward compatible in that JE files created with earlier releases can be read when opened with JE 6.3 or later. The change is not backward compatible in that files created with JE 6.3 or later cannot be read by earlier releases. After an existing environment is opened read/write using JE 6.3, the environment can no longer be read by earlier releases.

Upgrading from JE 6.1 or earlier

In JE 6.2 the on-disk file format moved to 10. The file format change is forward compatible but not backward compatible, as usual.

Upgrading from JE 6.0 or earlier

There was no file format change in JE 6.1. An API change in JE 6.1.3 [#23330] requires application changes if write operations are performed on a non-replicated database in a replicated environment. A code change is necessary for applications with the following characteristics:

A ReplicatedEnvironment is used.
A non-replicated, transactional Database is accessed (DatabaseConfig.setReplicated(false) and setTransactional(true) are called) in this environment.
When writing to this database, an explicit (non-null) Transaction is specified.

In order to perform write operations in such cases, the application must now call TransactionConfig.setLocalWrite(true) and use this configuration to create a Transaction for performing writes to the non-replicated database.

In addition, it is no longer possible to use a single transaction to write to both replicated and a non-replicated databases. IllegalOperationException will be thrown if this is attempted.

These changes were necessary to prevent corruption when a transaction contains write operations for both replicated and non-replicated databases, and a failover occurs that causes a rollback of this transaction. The probability of corruption is low, but it can occur under the right conditions.

For more information see the javadoc for TransactionConfig.setLocalWrite(true), and the "Non-replicated Databases in a Replicated Environment" section of the ReplicatedEnvironment class javadoc.

Upgrading from JE 5.0 or earlier

In addition to the file format changes, a change was made involving partial Btree and duplicate comparators. Partial comparators are an advanced feature that few applications use. As of JE 6.0, using partial comparators is not recommended. Applications that do use partial comparators must change their comparator classes to implement the new PartialComparator tag interface, before running the application with JE 6. Failure to do so may cause incorrect behavior during transaction aborts. See the PartialComparator javadoc for more information.

Upgrading from JE 4.1 or earlier

There are two important notes about the file format change in JE 5.0.

The file format change enabled significant improvements in operation performance, memory and disk footprint, and concurrency of databases with duplicate keys. Due to these changes, an upgrade utility must be run before opening an environment with this release, if the environment was created using JE 4.1 or earlier. See the Upgrade Procedure below for more information.
An application which uses JE replication may not upgrade directly from JE 4.0 to JE 5.0 or later. Instead, the upgrade must be done from JE 4.0 to JE 4.1 and then to JE 5.0 or later. Applications already at JE 4.1 are not affected. Upgrade guidance can be found in the new chapter, "Upgrading a JE Replication Group", in the "Getting Started with BDB JE High Availability" guide.

Due to the format changes in JE 5, a special utility program must be run for an environment created with JE 4.1 or earlier, prior to opening the environment with JE 5.0 or later. The utility program is part of JE 4.1. JE 4.1.20, or a later version of JE 4.1, must be used.

One of two utility programs must be used, which are available in the release package for JE 4.1.20, or a later release of JE 4.1. If you are currently running a release earlier than JE 4.1.20, then you must download the latest JE 4.1 release package in order to run these utilities.

The steps for upgrading are as follows.

Stop the application using BDB JE.

Run the DbPreUpgrade_4_1 or DbRepPreUpgrade_4_1 utility. If you are using a regular non-replicated Environment:

    java -jar je-4.1.20.jar DbPreUpgrade_4_1 -h <dir>

If you are using a JE ReplicatedEnvironment:

    java -jar je-4.1.20.jar DbRepPreUpgrade_4_1
         -h <dir>
         -groupName <group name>
         -nodeName <node name>
         -nodeHostPort <host:port>

Finally, start the application using the current JE 5.0 (or later) release of BDB JE.

The second step -- running the utility program -- does not perform data conversion. This step simply performs a special checkpoint to prepare the environment for upgrade. It should take no longer than an ordinary startup and shutdown.

During the last step -- when the application opens the JE environment using the current release (JE 5 or later) -- all databases configured for duplicates will automatically be converted before the Environment or ReplicatedEnvironment constructor returns. Note that a database might be explicitly configured for duplicates using DatabaseConfig.setSortedDuplicates(true), or implicitly configured for duplicates by using a DPL MANY_TO_XXX relationship (Relationship.MANY_TO_ONE or Relationship.MANY_TO_MANY).

The duplicate database conversion only rewrites internal nodes in the Btree, not leaf nodes. In a test with a 500 MB cache, conversion of a 10 million record data set (8 byte key and data) took between 1.5 and 6.5 minutes, depending on number of duplicates per key. The high end of this range is when 10 duplicates per key were used; the low end is with 1 million duplicates per key.

To make the duplicate database conversion predictable during deployment, users should measure the conversion time on a non-production system before upgrading a deployed system. When duplicates are converted, the Btree internal nodes are preloaded into the JE cache. A new configuration option, EnvironmentConfig.ENV_DUP_CONVERT_PRELOAD_ALL, can be set to false to optimize this process if the cache is not large enough to hold the internal nodes for all databases. For more information, see the javadoc for this property.

If an application has no databases configured for duplicates, then the last step simply opens the JE environment normally, and no data conversion is performed.

If the user fails to run the DbPreUpgrade_4_1 or DbRepPreUpgrade_4_1 utility program before opening an environment with JE 5 or later for the first time, an exception such as the following will normally be thrown by the Environment or ReplicatedEnvironment constructor:

  com.sleepycat.je.EnvironmentFailureException: (JE 6.0.1) JE 4.1 duplicate DB
  entries were found in the recovery interval. Before upgrading to JE 5.0, the
  following utility must be run using JE 4.1 (4.1.20 or later):
  DbPreUpgrade_4_1.  See the change log.
  UNEXPECTED_STATE: Unexpected internal state, may have side effects.
    at com.sleepycat.je.EnvironmentFailureException.unexpectedState(EnvironmentFailureException.java:376)
    at com.sleepycat.je.recovery.RecoveryManager.checkLogVersion8UpgradeViolations(RecoveryManager.java:2694)
    at com.sleepycat.je.recovery.RecoveryManager.buildTree(RecoveryManager.java:549)
    at com.sleepycat.je.recovery.RecoveryManager.recover(RecoveryManager.java:198)
    at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(EnvironmentImpl.java:610)
    ...

If the user fails to run the DbPreUpgrade_4_1 or DbRepPreUpgrade_4_1 utility program, but no exception is thrown when the environment is opened with JE 5 or later, this is probably because the application performed an Environment.sync before last closing the environment with JE 4.1 or earlier, and nothing else happened to be written (by the application or JE background threads) after the sync operation. In this case, running the upgrade utility is not necessary.

Changes in 7.5.11

Removed the following incorrect javadoc for cursor read operations:
In a replicated environment, an explicit transaction must have been specified when opening the cursor, unless read-uncommitted isolation is specified via the CursorConfig or LockMode parameter.

When a null Transaction parameter is specified for a read operation in a replicated environment, the default consistency (ReplicationConfig.CONSISTENCY_POLICY) is used.
[#26037] (7.5.0)

The data verifier has been enhanced to perform Btree verification. Btree verification is performed by the background data verifier, the DbVerify utility, the DbVerify.verify method, the Database.verify method and the Environment.verify method.
Previously, the DbVerify utility and the DbVerify/Database/Environment.verify methods performed a very rudimentary and inefficient form of verification. Btree verification now includes several different types of integrity checks and is performed more efficiently than before.
Background verification (see EnvironmentConfig.ENV_RUN_VERIFIER and VERIFY_SCHEDULE) now includes basic Btree verification and secondary index verification by default. There are two other types of verification can be enabled as described below. Previously, background verification only included log checksum verification (see EnvironmentConfig.VERIFY_LOG).
The javadoc for these parameters contains a complete description of the types of verification. Other changes to be aware of are:
- Only one instance of log corruption or basic Btree corruption now will be detected by data verification. Previously, the verifier would attempt to skip over such a detected corruption and continue, although this approach was unreliable. Now the Environment is always invalidated when such corruption is detected, and it isn't possible to continue.
- When index corruption is detected, the environment is not invalidated. Instead, the corrupt index (secondary database) is marked as corrupt in memory. All subsequent access to a corrupt index will now throw SecondaryIntegrityException. To correct the problem, the application may perform a full restore or rebuild the corrupt index. This new behavior applies whether the index corruption was detected during Btree verification or during normal access to the index.
- When basic Btree verification or log checksum verification fails, the Environment is invalidated (must be closed) and an EnvironmentFailureException is thrown. If the corruption is known to be persistent, the EnvironmentFailureException.isCorrupt method will return true. Additionally, when a persistent corruption is detected and the Environment is open for read-write access, a marker file named 7fffffff.jdb is created in the Environment directory that will prevent re-opening the environment. If an attempt is made to re-open the Environment, the original EnvironmentFailureException will be thrown. This is meant to safeguard against using a corrupt environment when the original exception is accidentally overlooked. While the marker file can be deleted to allow re-opening the environment, this is normally unsafe and is not recommended.
- The different types of verification can be enabled or disabled in the background data verifier using EnvironmentConfig.VERIFY_BTREE, VERIFY_SECONDARIES and VERIFY_DATA_RECORDS. Additional params control the Btree verification batch size and delay between batches: VERIFY_BTREE_BATCH_SIZE and VERIFY_BTREE_BATCH_DELAY.
- When using the DbVerify/Database/Environment.verify methods, the different types of verification can be enabled or disabled using new methods in the VerifyConfig class: setVerifySecondaries and setVerifyDataRecords. New methods also control the verification batch size and delay between batches: setBatchSize and setBatchDelay.
- When using the DbVerify command line, data record verification can be enabled using -vdr, and batch size/delay can be specified using -bs and -d. Note that secondary integrity verification is not possible using the command line because this feature requires the secondary databases to have been opened by the application.
- The Database.verify and Environment.verify methods now throw an EnvironmentFailureException (as described above) if verification fails. Previously, these methods did not give any indication of failure. This is a change in behavior.
- Updated existing javadoc in several cases where the javadoc was incorrect. Existing behavior was not changed in these cases.
  - Updated Environment.verify javadoc to indicate that the 'out' parameter is unused and VerifyConfig.setShowProgressStream should be used instead.
  - Updated VerifyConfig.getPrintInfo javadoc to indicate that the information in printed to System.err by default (not System.out) and the default is to use the stream specified by VerifyConfig.getShowProgressStream.
  - Updated the javadoc for VerifyConfig.setPropagateExceptions and VerifyConfig.setAggressive to note that these settings currently have no effect.
- Log verification (checksum validation) was previously supported. However, performance testing determined that log verification had a a negative impact on throughput and latency for some workloads. To avoid this, a delay between reads has been added. This delay can be configured using EnvironmentConfig.VERIFY_LOG_READ_DELAY, VerifyLog.setReadDelay and the -d command line arg.
[#25960] (7.5.1)

Configuration parameters for limiting disk usage have been added: Environment.MAX_DISK and FREE_DISK. MAX_DISK should be specified for JE HA applications when upgrading to this release, since data files will be reserved for potential replication to nodes that are out of contact. More reserved files are retained for potential replication in this release, as described further below. If MAX_DISK is not specified, all the free space on the volume (minus 5GB of free space, with the default setting of FREE_DISK) will eventually be used. The EnvironmentMutableConfig.setMaxDisk method is provided as a convenience for setting MAX_DISK.
Disk usage is now monitored and a new exception, DiskLimitException, is thrown when attempting a write operation when the threshold is in danger of being exceeded. In this situation, read operations are still allowed. Previously, the Environment was invalidated and closed when the volume was filled. Allowing read operations now provides partial availability in this situation. The FREE_DISK parameter also now prevents filling the disk completely, which eases manual recovery.
Although behavior is now improved when available space has been used, the application-level goal must be to prevent the situation entirely by monitoring disk usage and taking recourse before the situation occurs. To support this, new JE statistics have been added:
- activeLogSize: EnvironmentStats.getActiveLogSize()
- reservedLogSize: EnvironmentStats.getReservedLogSize()
- protectedLogSize: EnvironmentStats.getProtectedLogSize()
- protectedLogSizeMap: EnvironmentStats.getProtectedLogSizeMap()
- availableLogSize: EnvironmentStats.getAvailableLogSize()
We strongly recommend using availableLogSize to monitor disk usage and take corrective action well before this value reaches zero. Monitoring the file system size of the JE data files is not a good substitute for this, since the data files includes reserved files which will be deleted by JE automatically.
Additional details are listed below.
- DiskLimitException may be thrown by all record write operations, Environment.checkpoint, Environment.sync, and Environment.close (when the final checkpoint cannot be performed).
- The following HA config params are deprecated and no longer needed: ReplicationConfig.REP_STREAM_TIMEOUT, REPLAY_COST_PERCENT and REPLAY_FREE_DISK_PERCENT. Reserved files are now retained based on available disk space. EnvironmentConfig.MAX_DISK and FREE_DISK should be used instead.
  REPLAY_COST_PERCENT is no longer used. However, REP_STREAM_TIMEOUT is still used when some, but not all, nodes in a group have been upgraded to 7.5 or later. REPLAY_FREE_DISK_PERCENT is still used when it has been specified and is non-zero, and FREE_DISK has not been specified. In this case, REPLAY_FREE_DISK_PERCENT overrides the FREE_DISK default value. If both REPLAY_FREE_DISK_PERCENT and FREE_DISK are specified, an IllegalArgumentException is thrown.
- EnvironmentStats.getFileDeletionBacklog has been deprecated and always returns zero. Use EnvironmentStats.getProtectedLogSize() and getProtectedLogSizeMap() to monitor protected files.
- If EnvironmentConfig.CLEANER_BYTES_INTERVAL is zero or unspecified, it is now set to the minimum of EnvironmentConfig.LOG_FILE_MAX divided by four (this was the previous default) and 100 MB. The new 100 MB maximum is to ensure that the cleaner is woken frequently enough, so that reserved files are deleted quickly enough to avoid violating a disk limit. Use caution when overriding the default value.
- Previously, reserved files (files cleaned but not deleted) were not persistently marked as being reserved. So when the Environment was closed and re-opened, these files would be cleaned again. This re-cleaning was fairly quick because they were 0% utilized, but was a waste of resources nonetheless. Now, reserved files are marked as such in the cleaner's persistent metadata and this avoids re-cleaning.
- Previously, reserved files were included in the DbSpace output and shown as 0% utilized. They were also reflected in the total utilization, which was therefore inaccurate, since utilization applies to activeLogSize. Now, reserved files are omitted from the list of files and the total utilization. The amount of space used by reserved files is printed at the end of the summary. If the {@code -q} option is not specified, the reserved file numbers are also printed.
- Database.count and DiskOrderedCursor (which both internally use a disk-ordered scanner) now only protect active files from deletion. Previously they unnecessarily also protected reserved files.
- DbBackup now only protects active files from deletion. Previously it unnecessarily also protected reserved files. In addition, the DbBackup.removeFileProtection method has been added to allow removing protection from a file that has been copied, before calling DbBackup.endBackup.
- NetworkRestore now only protects active files, and the two most recent reserved files, from deletion. Previously it unnecessarily protected all reserved files. In addition, the protection is removed for files that have been transferred, prior to the completion of the entire restore.
- The totalLogSize and endOfLog stats (EnvironmentStats.getTotalLogSize and getEndOfLog) are no longer "slow" stats. They are returned by Environment.getStats regardless of the StatsConfig.getFast setting.
- The je.stat.csv file now contains all stats, not just "fast" stats. Previously, "slow" stats were omitted. Since the stat retrieval frequency is one minute and this is done by a background thread, there is no reason not to include all stats.
- Fixed a bug where per-Database cleaner metadata could accumulate under certain conditions.
[#25220] (7.5.3)

Fixed a compatibility problem with the Azul Zulu JVM. Previously the following exception would occur when using JE with Zulu:

The database environment could not be opened: java.lang.IllegalStateException:
Could not access Zing management bean. Make sure -XX:+UseZingMXBeans was
specified.

[#26163] (7.5.3)

Added ReplicationConfig.TXN_ROLLBACK_DISABLED to allow manual control over rollback, including rollback of transactions considered to be non-durable. See the javadoc for more information.
[#26220] (7.5.7)

Fixed a bug that could cause OutOfMemoryError when performing a network restore (NetworkRestore.execute) after an InsufficientLogException (ILE) is thrown. The ILE holds a reference to the internals (e.g., data cache) of the old environment handle. Previously, this reference was not cleared by the network restore. If the application then re-opened the environment, without discarding all references to the ILE, OutOfMemoryError could occur due to the presence of two data caches in the heap at the same time. Now the network restore clears the internal references when the restore is complete.
[#26305] (7.5.8)

Fixed a bug that could prevent performing a network restore (NetworkRestore.execute), after a prior network restore was aborted or incomplete for any reason. For example, this could occur if the process is killed during the first network restore, and then another network restore is attempted. The problem could occur only in an environment with a relatively large data set, specifically where at least one billion write transactions had been performed. An example stack trace is below.

java.lang.NumberFormatException: For input string: "7473413648"
    at java.lang.NumberFormatException.forInputString(
        NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:583)
    at java.lang.Integer.parseInt(Integer.java:615)
    at com.sleepycat.je.rep.InsufficientLogException.init(
        InsufficientLogException.java:218)
    at com.sleepycat.je.rep.impl.RepImpl.handleRestoreRequired(
        RepImpl.java:2296)
    at com.sleepycat.je.recovery.RecoveryManager.findEndOfLog(
        RecoveryManager.java:543)
    at com.sleepycat.je.recovery.RecoveryManager.recover(
        RecoveryManager.java:339)
    at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(
        EnvironmentImpl.java:841)
    at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(DbEnvPool.java:222)
    at com.sleepycat.je.Environment.makeEnvironmentImpl(Environment.java:267)
    at com.sleepycat.je.Environment.init(Environment.java:252)
    at com.sleepycat.je.rep.ReplicatedEnvironment.init(
        ReplicatedEnvironment.java:607)
    at com.sleepycat.je.rep.ReplicatedEnvironment.init(
        ReplicatedEnvironment.java:466)
...

This has been fixed. Without the fix, a workaround for the problem is to remove all the .jdb files from the destination node, before performing the network restore.

[#26311] (7.5.8)

Fixed an incorrect assertion when CLEANER_FORCE_CLEAN_FILES is specifid, and a specified file is already being cleaned. An example stack traced is below:

java.lang.AssertionError
at com.sleepycat.je.cleaner.FileSelector.selectFileForCleaning(FileSelector.java:193)
at com.sleepycat.je.cleaner.FileProcessor.doClean(FileProcessor.java:395)
at com.sleepycat.je.cleaner.Cleaner.doClean(Cleaner.java:670)
...

[#26326] (7.5.9)

Changes in 7.4.5

Fixed an internal deadlock between the following internal classes: ExpirationProfile, IN, FileSelector. This deadlock occurred very rarely (only once in our testing). It did not cause a persistent problem -- restarting the process was a safe workaround. [#25613] (7.4.1)

EnvironmentConfig.CLEANER_FORCE_CLEAN_FILES has been made mutable. [#25821] (7.4.2)

The OperationResult.isUpdate() method has been added for distinguishing inserts and updates performed by a Put.OVERWRITE operation. [#25882] (7.4.2)

Fixed unsafe file deletion issue in network restore. If the network restore was performed on a node without closing the environment, the deletion of obsolete log files was considered an unsafe operation that caused the restore to fail. The error message was:

  com.sleepycat.je.EnvironmentFailureException:../env Log file 00000000.jdb
  was deleted unexpectedly. LOG_UNEXPECTED_FILE_DELETION: A log file was
  unexpectedly deleted, log is likely invalid. Environment is invalid and must
  be closed. Originally thrown by HA thread: REPLICA 3(-1)

[#25834] (7.4.3)

Logging of internal nodes (INs) has been reduced when deleting many records in a contiguous key range. [#25939] (7.4.3)

Fixed a bug that could have caused duplicate records to be returned via the iterator() method of the DPL and Collections API. The iterator reads records in batches, and if a record at the end of the last batch was deleted by another thread, fetching the next batch could have read (and later returned via the iterator) duplicate records, depending on thread timing. [#25976] (7.4.3)

Fixed a bug that prevented LogOverwriteException from being thrown when assertions were disabled. LogOverwriteException is thrown to prevent creation of an invalid backup, although this can only happen in rare cases and only on an HA replica node. See the LogOverwriteException javadoc for more information. [#25989] (7.4.4)

Fixed a bug that caused the following assertion to fire when using a Database in deferred-write mode (DatabaseConfig.setDeferredWrite(true)) for which data was previously written in normal (non-deferred-write) mode.
```
java.lang.AssertionError
  com.sleepycat.je.tree.BIN.shouldLogDelta(BIN.java:1927)
  ...
```
[#25999] (7.4.4)

Changes in 7.3.7

EnvironmentConfig.LOG_N_DATA_DIRECTORIES has been deprecated. This feature is not known to provide benefits beyond that of a simple RAID configuration and will be removed in the next release, which is slated for mid-April, 2017.

Added Arbiter functionality that adds additional write availability for replication groups that have two Electable members. For details see the javadoc for com.sleepycat.je.rep.arbiter.Arbiter. [#25567] (7.3.0)

Operation throughput statistics have been simplified and improved. Previously, these statistics represented API calls rather than CRUD operations which caused confusion when a single API call performed multiple CRUD operations, some CRUD operations (key search operations on any node, and all operations on a replica node) were missing, the operation statistics were not included in the EnvironmentStats.toString result, and none of the operation statistics were available via EnvironmentStats getter methods. Previously the throughput stats, listed below, were only visible via the je.stat.csv file.

    Name
    ----
    dbDelete
    dbGet
    dbGetSearchBoth
    dbPut
    dbPutNoDupData
    dbPutNoOverWrite
    cursorDelete
    cursorGetCurrent
    cursorGetFirst
    cursorGetLast
    cursorGetNext
    cursorGetNextDup
    cursorGetNextNoDup
    cursorGetPrev
    cursorGetPrevDup
    cursorGetPrevNoDup
    cursorPut
    cursorPutCurrent
    cursorPutNoDupData
    cursorPutNoOverwrite
    secondaryCursorDelete
    secondaryCursorGetCurrent
    secondaryCursorGetFirst
    secondaryCursorGetLast
    secondaryCursorGetNext
    secondaryCursorGetNextDup
    secondaryCursorGetNextNoDup
    secondaryCursorGetPrev
    secondaryCursorGetPrevDup
    secondaryCursorGetPrevNoDup
    secondaryDbDelete
    secondaryDbGet
    secondaryDbGetSearchBoth

Now, the following statistics representing CRUD operations are output in the je.stats.cvs file and the EnvironmentStats.toString method, are included for all nodes including replicas, and are available via new EnvironmentStats getter methods. These replace the statistics listed above.

    Name                   EnvironmentStats method
    ----                   -----------------------
    priSearch              getPriSearchOps()
    priSearchFail          getPriSearchFailOps()
    secSearch              getSecSearchOps()
    secSearchFail          getSecSearchFailOps()
    priPosition            getPriPositionOps()
    secPosition            getSecPositionOps()
    priInsert              getPriInsertOps()
    priInsertFail          getPriInsertFailOps()
    secInsert              getSecInsertOps()
    priUpdate              getPriUpdateOps()
    secUpdate              getSecUpdateOps()
    priDelete              getPriDeleteOps()
    priDeleteFail          getPriDeleteFailOps()
    secDelete              getSecDeleteOps()

The new statistics should be considered internal operations or units of work rather than API calls. This approach is used to allow correlating operations to performance measurements. It also reduces the number of statistics by more than half. The javadoc of the new EnvironmentStats getter methods describe the mapping from API calls to operation statistics.

[#23792] (7.3.0)

Data corruption is now detected as soon as possible by using an internal JE background task. This detects data corruption caused by media/disk failure by reading the log sequentially and verifying checksums. This is the equivalent of running the current DbVerifyLog utility, but it is performed automatically and periodically. The schedule for performing verification can be controlled by the new EnvironmentConfig.ENV_RUN_VERIFIER, VERIFY_SCHEDULE and VERIFY_LOG parameters. By default, verification is on and occurs once a day at midnight, local time.
When corruption is detected, the Environment will be invalidated and an EnvironmentFailureException will be thrown. Applications catching this exception can call the new EnvironmentFailureException.isCorrupted method to determine whether corruption was detected.
If isCorrupted returns true, a network restore (or restore from backup) should be performed to avoid further problems. The advantage of performing verification frequently is that a problem may be detected sooner than it would be otherwise. For HA applications, this means that the network restore can be done while the other nodes in the group are up, minimizing exposure to additional failures.
[#25221] (7.3.0)

Repeat-fault reads have been eliminated, for the most part, for LNs (Btree leaf nodes, which represent record data on disk.) Previously, if an LN's on-disk size was greater than EnvironmentConfig.LOG_FAULT_READ_SIZE (2kB by default), two reads would be required to fetch the LN from disk. The first read would always include the log entry header, which contains the exact entry size, and the second read (repeat-read) was needed to read the entire entry. The second read includes the entire entry, although normally it will be cached by the file system.
Now, only a single read is needed because the last logged size for LNs is now stored in the Btree, for all LNs written with JE 6.0 and later, and this can be used to determine the exact size needed for the read buffer. The benefits of this change are 1) the amount of IO is reduced (although the repeat-read normally reads data that is cached by the file system), and 2) the statistics describing IO activity are simpler to analyze without the repeat-reads in the picture.
Note that INs (Btree internal nodes) can still cause repeat-reads when they are fetched, because the last logged size for INs is not stored in the Btree. However, in many applications all INs are cached and therefore INs are rarely read from disk (except during a cache warm-up period). The nRepeatFaultReads statistic (EnvironmentStats.getNRepeatFaultReads) indicates the number of repeat-reads.
[#25387] (7.3.0)

Several bugs were fixed related to performing a preload (Database.preload or Environment.preload) when an off-heap cache is configured (via EnvironmentConfig.setOffHeapCacheSize). These bugs sometimes caused an incomplete preload as well as producing an incorrect (corrupt) data set. In releases prior to 7.3, preload should not be used with an off-heap cache. [#25594] (7.3.1)

Network restores are instigated by a JE HA application when an environment open results in an InsufficientLogException. If a network restore is interrupted, the application should retry until it succeeds. Failing to do so might result in an environment log that is corrupted or inconsistent. This JE release adds a new mechanism to persistently mark that a network restore has started, and to prevent inadvertent use of the environment before the restore has completed. The marker file is named 7fffffff.jdb, and is recognized and managed by JE. The required steps for handling an InsufficientLogException are unchanged; the marker file is an internal mechanism.
[#25369] (7.3.1)

Fixed a bug that prevented the transaction timeout for a write operation from being honored in JE HA applications. When a transaction's ReplicaAckPolicy required waiting for a replica, the timeout was not always honored and the transaction sometimes took longer than the specified timeout. [#25692] (7.3.4)

Preload (Database.preload and Environment.preload) has been changed so that it does not populate the off-heap cache. Only the main cache (in the Java heap) is now populated. This was done to avoid a corruption problem linked to preload and the off-heap cache. Population of the off-heap cache will be added in a future release. Note that when an off-heap cache is configured, preload will not populate it, but other operations will populate it as data is evicted from the main cache. [#25594] (7.3.7)

Changes in 7.2.8

Fixed a problem where Environment.removeDatabase or truncateDatabase may have taken a long time to complete, due to internal retries. [#25361] (7.2.0)

Reduced GC overhead by avoiding the re-creation of internal lock objects, in cases where a record is locked by only one thread/transaction at a time. This overhead was introduced when deadlock detection was added in JE 7.1 [#16260]. The overhead is small, but could have impacted certain critical code paths, such as transaction replay on an HA replica node.
[#25355] (7.2.0)

Improved support for JDK 9. (Note that JDK 9 is not officially supported until it becomes generally available.) Previously, using JE with JDK 9 would cause the following exception:

  java.lang.IllegalStateException: java.lang.IllegalAccessException: class
  com.sleepycat.je.utilint.JVMSystemUtils cannot access class
  sun.management.BaseOperatingSystemImpl (in module java.management) because
  module java.management does not export sun.management to unnamed module
  @73846619

A workaround for this problem was to specify the following JVM option:

  -XaddExports:java.management/sun.management=ALL-UNNAMED

Specifying this option is no longer necessary. [#25383] (7.2.0)

Made several changes to make NullPointerExceptions less likely when closing an Environment. NullPointerException sometimes occurs when one thread is calling Environment.close and other threads (either application threads or internal JE threads) are concurrently accessing the Environment. It is still possible for NullPointerException and other unexpected exceptions to occur, but they should now happen less frequently, and IllegalStateException should normally be thrown instead.
Several additional fixes were made as a result of these changes:
- When a database is closed, Database.getDatabaseName now throws IllegalStateException. Previously, it returned null and this was not documented. This could have caused NullPointerException in the application.
- When a database is closed, Database.getConfig now throws IllegalStateException. Previously, it returned a non-null, but sometimes incorrect, configuration.
- When an environment is closed, Environment.printStartupInfo() now throws IllegalStateException; previously NullPointerException was thrown. As before, this method may be called when the environment is invalid but not yet closed, but now this behavior is documented.
- As before, the Environment.getConfig and getMutableConfig methods may be called when the environment is invalid but not yet closed, but now this behavior is documented.
- When an environment is invalid but not yet closed, and the Environment.setMutableConfig method is called, an EnvironmentFailureExcpetion is now thrown. Previously, the method's behavior in this case was undefined.
- When an environment is closed or invalid, ReplicatedEnviornment.transferMaster now throws IllegalStateException or EnvironmentFailureExcpetion. Previously a NullPointerException was thrown.
[#21590] (7.2.1)

Fixed a problem where checkpointing sometimes did not occur after log cleaning when application write operations stopped, preventing the reclaiming of disk space. This was a common problem with tests that expect disk space to be reclaimed. In production systems it could also be a problem during repair of an out-of-disk situation. See the javadoc for the configuration property, EnvironmentConfig.CLEANER_WAKEUP_INTERVAL, for details.
Note that an earlier fix [#23180] in JE 7.1 caused cleaning to occur in this situation, but a checkpoint is also needed to reclaim disk space after cleaning. In addition, the earlier fix was not reliable in certain cases where the cleaner thread awoke concurrently with the last write operation.
[#25364] (7.2.1)

Improved behavior and error handling support for an invalidated Environment. When an Environment is invalidated due to an EnvironmentFailureException, the user must call Environment.close(). Calls to any other JE methods will re-throw the invalidating EnvironmentFailureException. In addition, this exception may need special handling by the application, for example, an InsufficientLogException (which extends EnvironmentFailureException) must be handled by performing a network restore.
Several changes have been made to make this process simpler and more reliable.
- The first invalidating EnvironmentFailureException is now saved internally, and this exception is re-thrown when making a JE API call (other than Environment.close). Previously, when multiple EnvironmentFailureException occurred, the last one thrown was saved and re-thrown.
  (After the environment is invalidated by an EnvironmentFailureException, other EnvironmentFailureExceptions may be thrown later as side effects of the original problem, or possibly as separate problems. It is normally the first invalidating exception that is most relevant.)
- The Environment.getInvalidatingException method has been added. This returns the invalidating exception described above.
- The Environment.isClosed method has been added. The existing Environment.isValid returns false in two cases: when an environment is closed, and when it is invalid but not yet closed. This new isClosed method can be used to distinguish between these two cases. The javadoc for isValid was clarified accordingly.
[#25248] (7.2.1)

Detect unexpected JE log file deletions. Normally all JE log file deletions should be performed as a result of JE log cleaning. If an external file deletion is detected, JE assumes this was accidental. This will cause the environment to be invalidated and all methods will throw EnvironmentFailureException. [#25201] (7.2.2)

Enhanced the background log flushing capability in JE HA, and made this feature available with or without HA.
Previously, the ReplicationConfig.RUN_LOG_FLUSH_TASK and LOG_FLUSH_TASK_INTERVAL parameters specified whether and how often JE HA would periodically perform a flush and fsync, to force NO_SYNC or WRITE_NO_SYNC transactions to the file system and to the storage device. The default interval was 5 minutes. These parameters are now deprecated. For backward compatibility information, see the javadoc for these parameters.
In place of the deprecated HA parameters, the EnvironmentConfig.LOG_FLUSH_NO_SYNC_INTERVAL and LOG_FLUSH_SYNC_INTERVAL parameters have been added. These specify two separate intervals for flushing to the file system and the storage device, with default values of 5 seconds and 20 seconds, respectively. Frequent periodic flushing to the file system provides improved durability for NO_SYNC transactions. Without this flushing, if application write operations stop, then some number of NO_SYNC transactions would be left in JE memory buffers and would be lost in the event of a crash. For HA applications, this flushing reduces the possibility of RollbackProhibitedException.
[#25417] (7.2.2)

DbCacheSize has been improved for applications using CacheMode.EVICT_LN and an off-heap cache. This change applies when the -offheap argument is specified. The -maincache argument may now be omitted, and the size of the main cache is assumed to be the amount needed to hold all internal nodes (INs). Previously, it was difficult to use DbCacheSize to determine the main and off-heap cache sizes when using EVICT_LN, because DbCacheSize required specifying the main cache size and assumed that LNs would be stored in the main cache (when there was room).
[#25380] (7.2.6)

Changes in 7.1.9

Fixed a bug that might have caused data corruption. Multi-threaded writes were incorrectly allowed during recovery, due to eviction. The smaller the cache relative to the recovery interval and data set size, the more likely this was to occur. This could have caused corruption, but this was never confirmed.
Note that the corruption problem that motivated this fix occurred with an ext3 file system with a default configuration (write barrier not enabled). This is not recommended for JE, because JE relies on ordered writes. However, we don't have any proof that the problem was ext3 specific, because it was not reproducible.
During testing of this fix, a separate problem was fixed in the exception listener mechanism (EnvironmentConfig.setExceptionListener). Previously, when a JE background thread threw an Error (due to an assertion or out-of-memory condition, for example), this was not reported to the listener. Now, the EnvironmentFailureException, which is created as a result of the Error, is reported to the listener.
In addition, when an unhandled exception occurred in the background eviction threads, an EnvironmentFailureException was not created, and so the Environment was not invalidated. This was another reason for the lack of notifications to the exception listener. This has been corrected.
Note that when using a shared cache, unhandled exceptions during eviction do not always invalidate the Environment or cause exception listener events. This issue is not addressed by the fixes mentioned.
[#25084] (7.1.0)

Changes to track durable transaction commits (transaction durability requiring acknowledgements from at least a simple majority of nodes) explicitly in the JE HA log. Only durable transaction commits now count towards the rollback limit specified in com.sleepycat.je.rep.ReplicationConfig.TXN_ROLLBACK_LIMIT, thus allowing for automatic rollback and recovery in more cases.
[#25057] (7.1.0)

Fixed a bug that could prevent an HA internal thread from exiting on the master node, preventing internal state from being updated, and potentially causing disk usage to grow on all nodes. The internal thread also cannot be interrupted, causing a hang. An example thread dump for JE 5.0.98 is below.

"Feeder Input for rg2-rn1" #93465 daemon prio=5 os_prio=0 tid=0x00007fb40c028800 nid=0x109c runnable [0x00007fb3757d6000]
    java.lang.Thread.State: RUNNABLE
         at java.lang.Throwable.fillInStackTrace(Native Method)
         at java.lang.Throwable.fillInStackTrace(Throwable.java:783)
         - locked <0x00000003d0ae00e0> (a java.lang.IllegalArgumentException)
         at java.lang.Throwable.(Throwable.java:250)
         at java.lang.Exception.(Exception.java:54)
         at java.lang.RuntimeException.(RuntimeException.java:51)
         at java.lang.IllegalArgumentException.(
            IllegalArgumentException.java:42)
         at java.nio.Buffer.position(Buffer.java:244)
         at com.sleepycat.je.log.FileReader.threadSafeBufferPosition(
            FileReader.java:920)
         at com.sleepycat.je.log.FileReader$ReadWindow.fillFromFile(
            FileReader.java:1185)
         at com.sleepycat.je.log.FileReader$ReadWindow.slideAndFill(
            FileReader.java:1063)
         at com.sleepycat.je.log.FileReader.setBackwardPosition(
            FileReader.java:587)
         at com.sleepycat.je.log.FileReader.getLogEntryInReadBuffer(
            FileReader.java:429)
         at com.sleepycat.je.log.FileReader.readNextEntryAllowExceptions(
            FileReader.java:256)
         at com.sleepycat.je.log.FileReader.readNextEntry(FileReader.java:229)
         at com.sleepycat.je.rep.stream.FeederSyncupReader.scanBackwards(
            FeederSyncupReader.java:123)
         at com.sleepycat.je.rep.stream.FeederReplicaSyncup.
            makeResponseToEntryRequest(FeederReplicaSyncup.java:283)
         at com.sleepycat.je.rep.stream.FeederReplicaSyncup.execute(
            FeederReplicaSyncup.java:100)
         at com.sleepycat.je.rep.impl.node.Feeder$InputThread.run(
            Feeder.java:413)

[#25088] (7.1.0)

Deadlock detection has been implemented to improve performance and behavior when lock conflicts occur due to a deadlock. Performance is improved when the deadlock can be detected without blocking or blocking for a shorter time period, since the deadlock can be broken sooner and this can increase concurrency. Behavior is improved because DeadlockException is now thrown when a deadlock is detected, more debugging information is included in the exception, and deadlock detection is reliable.
In earlier releases, a LockTimeoutException was eventually thrown when a deadlock occurred, but only after the lock timeout expired. This exception sometimes contained information about a potential deadlock, but that information was not always correct.
Specific changes include:
- DeadlockException is now thrown when a deadlock is detected. Note that LockTimeoutException is still thrown when the lock timeout expires and a deadlock is not detected. TransactionTimeoutException is thrown when the transaction timeout expires and a deadlock is not detected.
- Deadlock detection is performed when a lock conflict is detected. A new configuration parameter, EnvironmentConfig.LOCK_DEADLOCK_DETECT, can be used to disable deadlock detection, By default, deadlock detection is enabled. See EnvironmentConfig.LOCK_DEADLOCK_DETECT for more details about the deadlock detection procedure.
- When deadlock detection is enabled, another new parameter, EnvironmentConfig.LOCK_DEADLOCK_DETECT_DELAY, may be used to improve performance under certain circumstances. By default this is set to zero, meaning no special delay.
- EnvironmentConfig.LOCK_OLD_LOCK_EXCEPTIONS is now deprecated and has no effect, as if were set to false. Also, LockNotGrantedException has been removed; it was replaced by LockNotAvailableException in JE 3.3. In addition, TransactionTimeoutException is always thrown when a transaction times out, not DeadlockException.
  
  Historical Note:
  
  In JE releases 3.3 and earlier, {@link DeadlockException} or a subclass of it was always thrown when a lock conflict occurred. Applications typically caught {@link DeadlockException} in order to detect lock conflicts and determine whether to retry a transaction. {@link DeadlockException} itself was thrown when a lock or transaction timeout occurred and {@link LockNotGrantedException} (a subclass of {@link DeadlockException}) was thrown when a lock conflict occurred for a no-wait transaction (see {@link TransactionConfig#setNoWait}).
  In all releases after JE 3.3, new exceptions and the new base class {@link LockConflictException} are available. {@link LockConflictException} should be caught to handle lock conflicts in a general manner, instead of catching {@link DeadlockException}.
  In all releases after JE 3.3, LockNotGrantedException was replaced by LockNotAvailableException. LockNotGrantedException was deprecated because it misleadingly extended DeadlockException. Now in JE 6.5, LockNotGrantedException has been removed.
[#16260] (7.1.1)

Fixed a bug that impacts the use of the Serializable isolation mode. When multiple threads were performing read and write operations, phantom prevention did not work in certain cases. [#25149] (7.1.1)

Fixed a problem where cleaning sometimes did not occur after application write operations stopped. This was a common problem with tests that expect disk space to be reclaimed. In production systems it could also be a problem during repair of an out-of-disk situation. See the javadoc for the new configuration property, EnvironmentConfig.CLEANER_WAKEUP_INTERVAL, for details.
(Note that this fix does not cause checkpointing to occur, and a checkpoint is sometimes needed to reclaim disk space after cleaning. A later fix in JE 7.2 [#25364] corrects this problem as well.)
[#23180] (7.1.1)

Fixed two bugs that could cause mutex deadlocks during Environment.close() and ReplicatedEnvrionment.shutdownGroup(). An example deadlock is shown below.

"ReplayThread" #37 daemon prio=5 os_prio=0 tid=0x00007fe11001f800 nid=0xfad
waiting for monitor entry [0x00007fe0fa1e6000]
   java.lang.Thread.State: BLOCKED (on object monitor)
    at com.sleepycat.je.dbi.EnvironmentImpl.removeConfigObserver(
        EnvironmentImpl.java:2675)
    - waiting to lock <0x00000000f131de08> (a com.sleepycat.je.rep.impl.RepImpl)
    at com.sleepycat.je.statcap.StatCapture.clearEnv(StatCapture.java:176)
    - locked <0x00000000f131f078> (a com.sleepycat.je.statcap.StatCapture)
    at com.sleepycat.je.dbi.EnvironmentImpl.shutdownStatCapture(
        EnvironmentImpl.java:2454)
    at com.sleepycat.je.dbi.EnvironmentImpl.shutdownDaemons(
        EnvironmentImpl.java:2345)
    at com.sleepycat.je.rep.impl.node.Replica.processShutdown(Replica.java:694)
    at com.sleepycat.je.rep.impl.node.Replica.access$1100(Replica.java:153)
    at com.sleepycat.je.rep.impl.node.Replica$ReplayThread.run(Replica.java:1229)

"UNKNOWN Node6(-1)" #1 prio=5 os_prio=0 tid=0x00007fe14400c000 nid=0xf81
waiting for monitor entry [0x00007fe14b9e4000]
   java.lang.Thread.State: BLOCKED (on object monitor)
    at com.sleepycat.je.statcap.StatCapture.clearEnv(StatCapture.java:170)
    - waiting to lock <0x00000000f131f078> (a
        com.sleepycat.je.statcap.StatCapture)
    at com.sleepycat.je.dbi.EnvironmentImpl.shutdownStatCapture(
        EnvironmentImpl.java:2454)
    at com.sleepycat.je.dbi.EnvironmentImpl.shutdownDaemons(
        EnvironmentImpl.java:2345)
    at com.sleepycat.je.dbi.EnvironmentImpl.doClose(EnvironmentImpl.java:1884)
    - locked <0x00000000f131de08> (a com.sleepycat.je.rep.impl.RepImpl)
    at com.sleepycat.je.dbi.DbEnvPool.closeEnvironment(DbEnvPool.java:374)
    - locked <0x00000000f131de08> (a com.sleepycat.je.rep.impl.RepImpl)
    - locked <0x00000000f1015b30> (a com.sleepycat.je.dbi.DbEnvPool)
    at com.sleepycat.je.dbi.EnvironmentImpl.close(EnvironmentImpl.java:1742)
    at com.sleepycat.je.Environment.close(Environment.java:445)
    - locked <0x00000000f2102ce8> (a com.sleepycat.je.rep.ReplicatedEnvironment)
    at com.sleepycat.je.rep.ReplicatedEnvironment.close(
        ReplicatedEnvironment.java:830)
    - locked <0x00000000f2102ce8> (a com.sleepycat.je.rep.ReplicatedEnvironment)
    ...

[#25195] (7.1.2)

A new exception, EnvironmentWedgedException, is now thrown by Environment.close when a badly behaved internal thread cannot be shutdown, and the current process must be shut down and restarted before re-opening the Environment. Prior to this change, when a thread could not be shut down, the application was not informed about the problem via an exception, and the badly behaved thread somtimes caused unpredictable behavior in the Environment, even if it were closed and re-opened. See EnvironmentWedgedException for more details.
[#25222] (7.1.3)

The default value for ReplicationConfig.REP_STREAM_TIMEOUT was changed from 24 hours to 30 minutes. The default value was changed to 30 minutes in the documentation in JE 6.0.5 [#22575], but code change was omitted, accidentally leaving the default value of 24 hours. A 30 minute value is much more reasonable than 24 hours, since during this period, files will be retained for feeding a dead or lagging replica, and this can cause an out-of-disk condition if enough data is written during this period. In the earlier change in JE 6.0.5, the REPLAY_COST_PERCENT and REPLAY_FREE_DISK_PERCENT parameters were added, and these also allow retention of files for replicas, but without the risk of creating an out-of-disk condition.
[#25254] (7.1.4)

Improved Environment.close for an invalid Environment, to reduce the probability of an OOME (OutOfMemoryError) when re-opening the Environment.
For an invalid Environment, previously JE did not attempt to close Databases during Environment.close. Also with an invalid Environment, Database.close simply re-threw the invalidating exception, and the Database was not closed.
The impact was that Environment and Database handles for a closed, invaid Environment would continue to refer to internal data structures and consequently to the cached data set. If another Environment was then opened, while referencing the previous Environment or Database handles, this could have caused OOME if the resident objects for both Environments did not fit in the heap. This was especially likely if recovery for the new Environment caused loading of a large data set.
The javadoc indicates that applications should discard all handles after closing an Environment. However, this is impractical at least in one use case: when asynchronously closing an Environment due to an exception and then re-opening it. When this is done asynchronously, it may be impractical to set all old handle references to null before opening the new handle. So in this case there will be a time interval where both Environments are referenced.
Now, Environment.close clears references to internal data structures in the Environment handle and all Database handles that have been opened via that Environment.
[#25238] (7.1.7)

Fixes an HA bug that manifested itself as a RollbackProhibitedException when replication nodes were running different JE versions and a version 6.4.15 Replica contacted a version 7 Master with a version less than 7.1.8.
[#25362] (7.1.8)

Changes in 7.0.5

A Time-To-Live (TTL) feature has been added to allow efficient purging of records whose lifetime is can be set in advance. Records can be assigned a TTL using WriteOptions.setTTL. The javadoc for the WriteOptions class contains a Time-To-Live section with more information about the TTL feature.
New 'get', 'put' and 'delete' API methods have been added to support the TTL feature and expansion of the API in the future. Each 'get' method has a ReadOptions parameter, and each 'put' and 'delete' method has a WriteOptions parameter. WriteOptions includes TTL parameters so that a TTL can be assigned to a record. The return value for the new methods is an OperationResult, or null if the operation fails. OperationResult includes the record's expiration time, for records that have been assigned a TTL. The new methods are as follows.
Note that the Collections API does not have new method signatures, since it conforms to the standard Java collections interfaces. Therefore, it is not currently possible to specify a TTL using the Collection API. However, it is possible to use the DPL API for writing data with a TTL, and then use EntityIndex.map or sortedMap to additionally use the Collections API.
```
com.sleepycat.je.Database

  OperationResult get(Transaction txn, DatabaseEntry key, DatabaseEntry data,
                      Get getType, ReadOptions options)

  OperationResult put(Transaction txn, DatabaseEntry key, DatabaseEntry data,
                      Put putType, WriteOptions options)

  OperationResult delete(Transaction txn, DatabaseEntry key,
                         WriteOptions options)

com.sleepycat.je.Cursor

  OperationResult get(DatabaseEntry key, DatabaseEntry data,
                      Get getType, ReadOptions options)

  OperationResult put(DatabaseEntry key, DatabaseEntry data,
                      Put putType, WriteOptions options)

  OperationResult delete(WriteOptions options)

com.sleepycat.je.SecondaryDatabase

  OperationResult get(Transaction txn, DatabaseEntry key, DatabaseEntry pKey,
                      DatabaseEntry data, Get getType, ReadOptions options)

  OperationResult delete(Transaction txn, DatabaseEntry key,
                         WriteOptions options)

com.sleepycat.je.SecondaryCursor

  OperationResult get(DatabaseEntry key, DatabaseEntry pKey,
                      DatabaseEntry data, Get getType, ReadOptions options)

  OperationResult delete(WriteOptions options)

com.sleepycat.je.ForwardCursor
com.sleepycat.je.JoinCursor
com.sleepycat.je.DiskOrderedCursor

  OperationResult get(DatabaseEntry key, DatabaseEntry data,
                      Get getType, ReadOptions options)
  // Get.NEXT and CURRENT only

com.sleepycat.persist.PrimaryIndex

  OperationResult put(Transaction txn, E entity,
                      Put putType, WriteOptions writeOptions)
  // Put.OVERWRITE and NO_OVERWRITE only

com.sleepycat.persist.EntityIndex

  EntityResult get(Transaction txn, K key,
                   Get getType, ReadOptions readOptions)
  // Get.SEARCH only, more types may be supported later

  OperationResult delete(Transaction txn, K key, WriteOptions writeOptions)

com.sleepycat.persist.EntityCursor

  EntityResult get(Get getType, ReadOptions readOptions)
  // All Get types except SEARCH_*, which may be supported later

  OperationResult update(V entity, WriteOptions writeOptions)

  OperationResult delete(WriteOptions writeOptions)
```
The 'put' methods are passed a Put enum value and the 'get' methods are passed a Get enum value. The enum values correspond to the methods of the older API. For example, Get.SEARCH corresponds to the older Cursor.getSearchKey method and Put.NO_OVERWRITE corresponds to the older Database.putNoOverwrite method. Future enhancements, like TTL, may be supported via the newer 'get' and 'put' methods, so we recommend that these methods are used instead of the older API methods. However, there are no plans to deprecate or remove the older methods at this time. In fact, the older methods still appear in most of the JE example programs and documentation.
ReadOptions and WriteOptions contain a CacheMode parameter for specifying the cache mode on a per-operation. ReadOptions also contains a LockMode property, which corresponds to the LockMode parameter of the older 'get' and 'put' methods. To ease the translation of existing code, a LockMode.toReadOptions method is provided.
Another API change has to do with key-only 'get' operations, where returning the record data is not needed. Previously, returning the data and its associated overhead could be avoided only by calling DatabaseEntry.setPartial. Now, null may be passed for the data parameter instead. In fact, null may now be passed for all "output parameters", in both the new and old versions of the 'get' and 'put' methods. For more information, see the "Input and Output Parameters" section of the DatabaseEntry class javadoc.
The JE cleaner has also been enhanced to perform purging of expired data. For each data file, a histogram of expired data sizes is stored and used by the cleaner. Along with the obsolete size information that the cleaner already maintains, the histogram allows knowing when a file is ready for cleaning. New related cleaner statistics are as follows:
- EnvironmentStats.getNLNsExpired - the number of expired LNs processed by the cleaner.
- EnvironmentStats.getCurrentMinUtilization - replacement for getLastKnownUtilization, which is now deprecated.
- EnvironmentStats.getCurrentMaxUtilization - the maximum utilization are often different than the minimum, when TTL is used.
- EnvironmentStats.getNCleanerTwoPassRuns - two-pass cleaning is used when the maximum and minimum diverge.
- EnvironmentStats.getNCleanerRevisalRuns - two-pass cleaning can result in revised expiration data.
Another indication of expired data is shown by the DbSpace utility. This now outputs minimum and maximum utilization and the total expired bytes. A new option for this utility, -t DATE-TIME, shows the utilization and expired bytes for a specified time.
The DbCacheSize utility now has a -ttl option. Specifying this option causes the estimated cache size to include space for an expiration time for each record.
The RecoveryProgress.POPULATE_EXPIRATION_PROFILE phase was added to indicate that the cleaner is reading the stored histograms into cache.
EnvironmentConfig.ENV_EXPIRATION_ENABLED is a new config param that is true by default, meaning that expired data is filtered from queries and purged by the cleaner. It might be set to false to recover data after an extended down time.
In addition, the cleaner "backlog" mechanism has been removed, meaning that EnvironmentStats.getCleanerBacklog and EnvironmentConfig.CLEANER_MAX_BATCH_FILES are now deprecated. The backlog mechansim has not been beneficial for some time and was due for removal. When using TTL, because two-pass cleaning can occur even when true utilization is below EnvironmentConfig.CLEANER_MIN_UTILIZATION, the cleaner backlog statistic would have been misleading.
[#16845] (7.0.0)

Fixed a bug causing the following exception. In JE versions from 6.2 to 6.4, this could occur when EnvironmentConfig.NODE_MAX_ENTRIES or DatabaseConfig.setNodeMaxEntries is more than 128, which is the default value.

Caused by: java.lang.ArrayIndexOutOfBoundsException: -96
    at com.sleepycat.je.tree.BINDeltaBloomFilter.setBit(
        BINDeltaBloomFilter.java:257)
    at com.sleepycat.je.tree.BINDeltaBloomFilter.add(
        BINDeltaBloomFilter.java:113)
    at com.sleepycat.je.tree.BIN.createBloomFilter(BIN.java:1863)
    at com.sleepycat.je.tree.IN.serialize(IN.java:6037)
    at com.sleepycat.je.tree.IN.writeToLog(IN.java:6021)
    at com.sleepycat.je.log.entry.INLogEntry.writeEntry(INLogEntry.java:349)
    at com.sleepycat.je.log.LogManager.marshallIntoBuffer(LogManager.java:731)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:346)
    ...

[#24896] (7.0.0)

Changes in 6.4.15

Made several minor improvements to off-heap cache behavior.
- The OffHeap:offHeapCriticalNodesTargeted statistic was added for monitoring off-heap critical eviction, which increases operation latency in application threads. See EnvironmentStats.getOffHeapCriticalNodesTargeted.
- To reduce off-heap critical eviction, the default for EnvironmentConfig.OFFHEAP_EVICT_BYTES was changed from 1MB to 50MB.
- To reduce off-heap evictor thread contention, the default for EnvironmentConfig.OFFHEAP_MAX_THREADS was changed from 10 to 3, and an internal check was added to reduce contention when all threads are busy.
[#23889] (6.4.10)

Fixed a bug that caused internal Btree corruption when using the off-heap cache and performing insertions. The bug was observed when using CacheMode.EVICT_BIN, but could also occur if BIN eviction is frequent for other reasons. The bug causes persistent corruption that would require reverting to a backup (or HA network restore) to correct. The bug was observed to cause one of the two following exceptions at the time the corruption was created.

The following assertion would rarely occur, and only if assertions were enabled of course.

com.sleepycat.je.EnvironmentFailureException: (JE 6.4.10)
UNEXPECTED_STATE: Unexpected internal state, may have side effects.
    at com.sleepycat.je.EnvironmentFailureException.unexpectedState(
    EnvironmentFailureException.java:397)
    at com.sleepycat.je.tree.IN.getKnownChildIndex(IN.java:782)
    at com.sleepycat.je.evictor.OffHeapCache.freeRedundantBIN(
    OffHeapCache.java:1974)
    at com.sleepycat.je.tree.IN.updateLRU(IN.java:695)
    at com.sleepycat.je.tree.IN.latchShared(IN.java:600)
    at com.sleepycat.je.recovery.DirtyINMap.selectDirtyINsForCheckpoint(
    DirtyINMap.java:277)
    at com.sleepycat.je.recovery.Checkpointer.doCheckpoint(
    Checkpointer.java:816)
    at com.sleepycat.je.recovery.Checkpointer.onWakeup(Checkpointer.java:593)
    at com.sleepycat.je.utilint.DaemonThread.run(DaemonThread.java:184)
    at java.lang.Thread.run(Thread.java:745)

The following assertion would occur more often, whether or not assertions were enabled.

com.sleepycat.je.EnvironmentFailureException: (JE 6.4.10)
UNEXPECTED_STATE_FATAL: Failed adding new IN ...
    at com.sleepycat.je.EnvironmentFailureException.unexpectedState(
    EnvironmentFailureException.java:441)
    at com.sleepycat.je.dbi.INList.add(INList.java:204)
    at com.sleepycat.je.tree.IN.addToMainCache(IN.java:2966)
    at com.sleepycat.je.tree.IN.postLoadInit(IN.java:2939)
    at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:2513)
    at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:2279)
    at com.sleepycat.je.tree.Tree.searchSplitsAllowed(Tree.java:1919)
    at com.sleepycat.je.tree.Tree.searchSplitsAllowed(Tree.java:1857)
    at com.sleepycat.je.tree.Tree.searchSplitsAllowed(Tree.java:1775)
    at com.sleepycat.je.tree.Tree.findBinForInsert(Tree.java:1746)
    at com.sleepycat.je.dbi.CursorImpl.insertRecordInternal(
    CursorImpl.java:1381)
    at com.sleepycat.je.dbi.CursorImpl.insertOrUpdateRecord(
    CursorImpl.java:1280)
    at com.sleepycat.je.Cursor.putNoNotify(Cursor.java:2504)
    at com.sleepycat.je.Cursor.putNotify(Cursor.java:2365)
    at com.sleepycat.je.Cursor.putNoDups(Cursor.java:2223)
    at com.sleepycat.je.Cursor.putInternal(Cursor.java:2060)
    at com.sleepycat.je.Cursor.put(Cursor.java:730)

[#24564] (6.4.11)

Fixed a bug that could cause queries to return the wrong result, and also could cause persistent Btree corruption. The bug is present in releases 6.3.0 to 6.4.11. The conditions for the bug are as follows.
- A custom key comparator must not be configured.
- The DB must not be a duplicates DB (because an internal key comparator is used).
- Key prefixing must be configured for the DB (or at least, it must have been configured when data was written).
- The bug will occur when the search key of an operation (either a read or a write operation, including internal operations such as cleaning and checkpointing) is a prefix of the common prefix for all the keys in an IN. In this case, if a custom comparator is not used, the default internal comparator will return a wrong result when comparing the search key with another key in the IN. This will in general result in wrong results and/or data corruption.
- For a query to return the wrong result, the specified search key must be a prefix of other keys in the DB. For example, key A is a prefix of key A1 and A2.
- For corruption to occur, some keys in the DB must be a prefix of other keys. For example, keys A, A1 and A2 are stored.
- In both cases above (a query with the wrong result and corruption), the smaller key which is a prefix of other keys must also be smaller or equal to JE's internal key prefix for the Btree internal node (IN) that is accessed. This means that all keys in the IN, or roughly 100 adjacent keys, must have this prefix.
[#24583] (6.4.12)

Fixed a bug in preload (Database.preload and Environment.preload) that prevented all data from being preloaded. It did not cause corruption of any kind, and the data that was not preloaded was still accessible, i.e., it would be loaded when acessed through normal API operations.
Data was missed by preload when BIN-deltas were present in cache. If the preload was performed immediately after opening the Environment, this would normally happen only after a crash-recovery (a normal shutdown did not occur). If the preload was performed later on, BIN-deltas might also be in cache due to eviction.
[#24565] (6.4.12)

Fixed a bug in preload (Database.preload and Environment.preload) that caused preloaded data to be evicted from cache by a subsequent operation using CacheMode.UNCHANGED.
[#24629] (6.4.14)

Fixed a bug where the information about lock owners and waiters in LockConflictException was sometimes incorrect due to a time window between detecting the lock conflict and constructing the exception. The fix applies to the LockConflictException.getOwnerTxnIds and getWaiterTxnIds methods, and to the two lines in the first part of the exception message starting with "Owners:" and "Waiters:".
In addition, the list of waiters will now contain the locker or Transaction requesting the lock, for which the LockConflictException is thrown.
The fix does NOT apply to the information output when EnvironmentConfig.TXN_DUMP_LOCKS is set to true. This information is by nature somewhat inaccurate, because normal locking operations are not frozen when this dump is occurring, so changes to the state of the lock table are occurring concurrently.
The fix also does NOT apply to the deadlock information that is sometimes included in the exception message. This information can also be inaccurate due to concurrent locking operations. This is a larger problem that will be fixed in a future release.
[#24623] (6.4.14)

Fixed a bug that could cause a "log file not found" exception during recovery, i.e., when opening the Environment. The circumstances that provoked this bug are:

The bug could only occur in Btrees with 4 or more levels, which typically means a single Database must have roughly one million records or more.
The bug is more likely to occur with insertion heavy workloads.
The bug has existed in all earlier versions of JE, but is more likely to occur in JE 6.2 and later.

The bug does not cause a permanent data corruption, if upgrading to JE 6.4.14 is possible. In other words, if the problem occurs in an earlier version, upgrading to 6.4.14 or later will allow the Environment to be opened.

Example exception:

Exception in thread "main" com.sleepycat.je.EnvironmentFailureException:
(JE 6.4.9) ... last LSN=0x20c7b6/0xa986dc LOG_INTEGRITY: Log information is
incorrect, problem is likely persistent. Environment is invalid and must be
closed.
        at com.sleepycat.je.recovery.RecoveryManager.traceAndThrowException(
            RecoveryManager.java:3176)
        at com.sleepycat.je.recovery.RecoveryManager.readINs(
            RecoveryManager.java:1039)
        at com.sleepycat.je.recovery.RecoveryManager.buildINs(
            RecoveryManager.java:842)
        at com.sleepycat.je.recovery.RecoveryManager.buildTree(
            RecoveryManager.java:757)
        at com.sleepycat.je.recovery.RecoveryManager.recover(
            RecoveryManager.java:387)
        at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(
            EnvironmentImpl.java:717)
        at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(
            DbEnvPool.java:254)
        at com.sleepycat.je.Environment.makeEnvironmentImpl(
            Environment.java:287)
        at com.sleepycat.je.Environment.(Environment.java:268)
        at com.sleepycat.je.Environment.(Environment.java:212)
        at com.sleepycat.je.util.DbDump.openEnv(DbDump.java:422)
        at com.sleepycat.je.util.DbDump.listDbs(DbDump.java:316)
        at com.sleepycat.je.util.DbDump.main(DbDump.java:296)
Caused by: com.sleepycat.je.EnvironmentFailureException:
(JE 6.4.9) ... fetchIN of 0x20c756/0x4e81bd parent IN=2785507 IN
class=com.sleepycat.je.tree.IN lastFullLsn=0x20c7af/0xc81b2d
lastLoggedLsn=0x20c7af/0xc81b2d parent.getDirty()=true state=0
LOG_FILE_NOT_FOUND: Log file missing, log is likely invalid. Environment is
invalid and must be closed.
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:2523)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:2293)
        at com.sleepycat.je.tree.Tree.getParentINForChildIN(Tree.java:1418)
        at com.sleepycat.je.recovery.RecoveryManager.recoverChildIN(
            RecoveryManager.java:1338)
        at com.sleepycat.je.recovery.RecoveryManager.recoverIN(
            RecoveryManager.java:1166)
        at com.sleepycat.je.recovery.RecoveryManager.replayOneIN(
            RecoveryManager.java:1130)
        at com.sleepycat.je.recovery.RecoveryManager.readINs(
            RecoveryManager.java:1021)
        ... 11 more
Caused by: java.io.FileNotFoundException: .../0020c756.jdb (No such file or directory)
        at java.io.RandomAccessFile.open(Native Method)
        at java.io.RandomAccessFile.(RandomAccessFile.java:241)
        at java.io.RandomAccessFile.(RandomAccessFile.java:122)
        at com.sleepycat.je.log.FileManager$DefaultRandomAccessFile.(
            FileManager.java:3226)
        at com.sleepycat.je.log.FileManager$6.createFile(
            FileManager.java:3254)
        at com.sleepycat.je.log.FileManager.openFileHandle(
            FileManager.java:1333)
        at com.sleepycat.je.log.FileManager.getFileHandle(
            FileManager.java:1204)
        at com.sleepycat.je.log.LogManager.getLogSource(LogManager.java:1136)
        at com.sleepycat.je.log.LogManager.getLogEntry(
            LogManager.java:823)
        at com.sleepycat.je.log.LogManager.getLogEntryAllowInvisibleAtRecovery(
            LogManager.java:788)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:2345)
        ... 17 more

Thanks to Alexander Kharichev for reproducing this bug and capturing the data files that allowed us to find the problem. This took many months of persistence, and special instrumentation for using with the CLEANER_EXPUNGE option in a production environment.

[#24663] (6.4.14)

Fixed a bug that caused PreloadStats.getNEmbeddedLNs to return zero when using PreloadConfig.setLoadLNs(false). getNEmbeddedLNs now returns the number of embedded LNs loaded into cache, irrespective of the setLoadLNs setting.
[#24688] (6.4.15)

Fixed a performance problem related to the off-heap cache. Previously, when the off-heap cache overflowed, BINs (bottom internal nodes) were evicted before evicting LNs (records or leaf nodes), when the LNs were in dirty BINs. The effect was that more read I/O was required to fetch the INs when they were needed. In general, disregarding the LRU, BINs should be kept in cache in preference to LNs, and the fix corrects the implementation of that policy.
In addition, a change was made to allow off-heap LNs to be evicted sooner, to to delay eviction of off-heap BINs (or their mutation to BIN-deltas). Previously, when a BIN was evicted from main cache and moved off-heap, its off-heap LNs were made "hot" in the off-heap cache. This no longer occurs.
[#24717] (6.4.25)

Changes in 6.4.9

Fixed a bug that (rarely) caused an exception such as the following, during shutdown of a ReplicatedEnvironment. This caused no persistent damage, but the unexpected runtime exception could cause exception handling problems or at least confusion.

com.sleepycat.je.EnvironmentFailureException.unexpectedException(
    EnvironmentFailureException.java:351)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:496)
    at com.sleepycat.je.log.LogManager.logItem(LogManager.java:438)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:350)
    at com.sleepycat.je.tree.LN.logInternal(LN.java:752)
    at com.sleepycat.je.tree.LN.optionalLog(LN.java:473)
    at com.sleepycat.je.dbi.CursorImpl.updateRecordInternal(
        CursorImpl.java:1689)
    at com.sleepycat.je.dbi.CursorImpl.insertOrUpdateRecord(
        CursorImpl.java:1321)
    at com.sleepycat.je.Cursor.putNoNotify(Cursor.java:2509)
    at com.sleepycat.je.Cursor.putNotify(Cursor.java:2370)
    at com.sleepycat.je.Cursor.putForReplay(Cursor.java:2038)
    at com.sleepycat.je.DbInternal.putForReplay(DbInternal.java:186)
    at com.sleepycat.je.rep.impl.node.Replay.applyLN(Replay.java:1012)
    ... 2 more
Caused by: java.lang.NullPointerException
    at com.sleepycat.je.rep.vlsn.VLSNIndex.decrement(VLSNIndex.java:526)
    at com.sleepycat.je.rep.impl.RepImpl.decrementVLSN(RepImpl.java:840)
    at com.sleepycat.je.log.LogManager.serialLogWork(LogManager.java:710)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:481)
    ... 13 more

[#24281] (6.4.0)

Fixed a recovery (startup) performance problem that occurred when extremely large numbers of .jdb files were present. For large data sets, the default file size (10 MB) results in large numbers of files. A directory listing of these files was performed by JE when reading the log sequentially during recovery, and this noticeably slowed down recovery. With this fix, recovery no longer performs a directory listing.
However, other utilities that read the entire log (e.g., DbPrintLog) must perform a directory listing to skip over gaps in the sequence of files numbers caused by log file deletion (cleaning). Therefore, when a large data set is expected or possible, the file size (EnvironmentConfig.LOG_FILE_MAX) should be configured to a larger size. A file size of one GB is recommended for large data sets.
[#24332] (6.4.0)

Fixed a transient problem for HA applications that resulted in an exception such as the following. This occurred when quorum was temporarily lost. The fix will prevent this exception from occurring. Note that even when the problem occurred, the node automatically recovered quorum, so the problem was not persistent.

com.sleepycat.je.EnvironmentFailureException: (JE 6.3.7) Problem in
ReadWindow.fill, reading from = 0 UNEXPECTED_EXCEPTION: Unexpected internal
Exception, may have side effects. MasterFeederSource fetching vlsn=5,096,275
waitTime=1000 Uncaught exception in feeder thread:Thread[Feeder Output for
rg1-rn5,5,main] Originally thrown by HA thread: MASTER rg1-rn1(1)
    at com.sleepycat.je.EnvironmentFailureException.unexpectedException(
        EnvironmentFailureException.java:366)
    at com.sleepycat.je.rep.stream.FeederReader$SwitchWindow.fillNext(
        FeederReader.java:572)
    at com.sleepycat.je.log.FileReader.readData(FileReader.java:822)
    at com.sleepycat.je.log.FileReader.readNextEntryAllowExceptions(
        FileReader.java:379)
    at com.sleepycat.je.log.FileReader.readNextEntry(FileReader.java:276)
    at com.sleepycat.je.rep.stream.FeederReader.scanForwards(
        FeederReader.java:308)
    at com.sleepycat.je.rep.stream.MasterFeederSource.getWireRecord(
        MasterFeederSource.java:100)
    at com.sleepycat.je.rep.impl.node.Feeder$OutputThread.writeAvailableEntries(
        Feeder.java:1219)
    at com.sleepycat.je.rep.impl.node.Feeder$OutputThread.run(Feeder.java:1109)
Caused by: java.io.FileNotFoundException:
/scratch/suitao/dctesting/kvroot/mystore/sn3/rg1-rn1/env/00000000.jdb (No such
file or directory)
    at java.io.RandomAccessFile.open(Native Method)
    at java.io.RandomAccessFile.<init>(RandomAccessFile.java:241)
    at java.io.RandomAccessFile.<init>(RandomAccessFile.java:122)
    at com.sleepycat.je.log.FileManager$DefaultRandomAccessFile.<init>(
        FileManager.java:3201)
    at com.sleepycat.je.log.FileManager$6.createFile(FileManager.java:3229)
    at com.sleepycat.je.log.FileManager.openFileHandle(FileManager.java:1308)
    at com.sleepycat.je.log.FileManager.getFileHandle(FileManager.java:1179)
    at com.sleepycat.je.rep.stream.FeederReader$SwitchWindow.fillNext(
        FeederReader.java:511)
    ... 7 more

[#24299] (6.4.0)

Added an off-heap cache capability. An off-heap cache can be used to utilize large memories more efficiently than when using the same memory for the file system cache, while avoiding the Java GC overheap associated with large Java heaps. See the EnvironmentMutableConfig.setOffHeapCacheSize javadoc for information on how to enable the cache and its impact on performance.
Please be aware of the following limitations in the initial release of this feature:
- The off-heap cache is not currently used for deferred-write and temporary databases, i.e., databases created using DatabaseConfig.setTemporary(true) or setDeferredWrite(true). For such databases, only the main (in-heap) cache is used.
- As described in the EnvironmentMutableConfig.setOffHeapCacheSize javadoc, the off-heap cache only works when Unsafe.allocateMemory is available in the JDK used to run the JE application. The Oracle JDK is compatible.
- When testing the off-heap cache on the IBM JDK, using Linux, we noticed that the per-memory block overhead is much higher than when using the Oracle JDK. We observed an extra 70 byte overhead per block that is allocated by Unsafe.allocateMemory. This overhead is not currently accounted for in our initial version of the off-heap allocator, so users of the IBM JDK should expect that more off-heap memory will be used than what DbCacheSize calculates and more than what the EnvironmentStats.getOffHeapTotalBytes method reports. We would like to solitic input on this issue from our users who are familiar with the internals of the IBM JDK.
- The Getting Started Guide does does not yet contain information about the off-heap cache. Please refer to the javadoc.
The following additional API additions are associated with the off-heap cache.
- EnvironmentMutableConfig.setOffHeapCacheSize (EnvironmentConfig.MAX_OFF_HEAP_MEMORY). This is the only configuration parameter that must be set to use the off-heap cache. See the setOffHeapCacheSize javadoc for details on the purpose and function of the off-heap cache.
- EnvironmentConfig.OFFHEAP_N_LRU_LISTS. Allows reducing contention among threads performing eviction, with the cost of reduced LRU accuracy.
- EnvironmentConfig.OFFHEAP_CORE_THREADS, OFFHEAP_MAX_THREADS, OFFHEAP_KEEP_ALIVE. Used to configure the thread pool for the off-heap evictor.
- EnvironmentConfig.ENV_RUN_OFFHEAP_EVICTOR. Used to disable the off-heap evictor thread for applications calling Environment.evictMemory explicitly.
- EnvironmentConfig.OFFHEAP_EVICT_BYTES. Determines the size of an eviction batch.
- EnvironmentConfig.OFFHEAP_CHECKSUM. Can be used for debugging.
- EnvironmentStats.getOffHeap*. These 20 new getter methods allow getting off-heap cache statistics.
[#23889] (6.4.1)

Several improvements were made to DiskOrderedCursor performance and behavior. These improvements also apply to Database.count, which uses the same internal scanning mechanism as DiskOrderedCursor.
- DiskOrderedCursor now no longer accumulates LSNs for data that is resident in the JE cache. Before, data resident in cache would sometimes be fetched from disk to avoid filling the output queue for the scan. This is no longer the case, and this has two important benefits:
  1. The semantics of a DiskOrderedCursor scan are now roughly the same as when using LockMode.READ_UNCOMMITTED. There is no longer a potential lag back to the last checkpoint. See the updated Consistency Guarantees section in the DiskOrderedCursor javadoc for details.
  2. Less read IO is performed in some cases.
  [#24226]
- To prevent applications from having to reserve memory in the Java heap for the DiskOrderedCursor, memory used by the DiskOrderedCursor is now subtracted from the JE cache budget. The maximum amount of such memory is specified, as before, using DiskOrderedCursorConfig.setInternalMemoryLimit. This is a behavior change and may require some applications to increase the JE cache size. [#24291]
- DiskOrderedCursor can now scan multiple databases using the new Environment.openDiskOrderedCursor method. When scanning multiple databases this method will provide better performance than scanning each database separately. [#24171]
- DiskOrderedCursor scans now uses shared latches on upper INs, instead of exclussive latches. This reduces contention between the DiskOrderedCursor scan and other Btree operations, such as CRUD operations. [#24192]
- Whenever possible, DiskOrderedCursor no longer makes copies of BIN-deltas found in the cache. This results in less memory useage (and consequently less read IO). [#24270]
(6.4.2)

Made improvements to the debug logging entries created to provide information about log files that were protected from deletion.
- Modified entries created by the cleaner to identify which log files were protected from deletion
- Modified entries created for replicated environments to provide information about the reason files were protected from deletion
- Changed the logging level for these entries to INFO to emphasize that the protection of files from deletion is expected behavior
[#24241] (6.4.2)

Fixed a bug where a Btree latch was not released when an Error was thrown by a file read, during a secondary DB lookup. This could cause an EnvironmentFailureException with the error message "Latch already held" at a later time in the same thread, or a latch deadlock in another thread. [#24375] (6.4.3)

Fixed a bug in Database.count that caused it to loop "forever" with a large out-of-cache data set. This also impacted Environment.truncateDatabase when 'true' was passed for the 'returnCount' param, since this causes Database.count to be called. [#24448] (6.4.7)

Fixed a bug that could cause incomplete results to be returned from a query using secondary indexes, when this query is performed on a replica and record deletions are being performed on the master (and being replayed on the replica). It could also cause LockConflictException to be thrown by the query on the replica in this situation, even when the application's operation order (locking order) should not cause a deadlock. [#24507] (6.4.8)

Changes in 6.3.8

Added EnvironmentStats.getNDirtyNodesEvicted and the corresponding statistic in the jestat.csv file. This can be used to determine how much logging and its associated costs (cleaning, etc) are being caused by eviction when the cache overflows. [#24086] (6.3.0)

Fixed a bug that resulted in an EnvironmentFailureException being thrown from the method Environment.beginTransaction(), when a replicated environment was closed at a master while new transactions were being concurrently initiated. The following representative stack trace is symptomatic of this problem (the specifics of the stack trace may vary depending on the JE release):

        ...
	at com.sleepycat.je.EnvironmentFailureException.unexpectedException(EnvironmentFailureException.java:351)
	at com.sleepycat.je.rep.utilint.RepUtils$ExceptionAwareCountDownLatch.awaitOrException(RepUtils.java:268)
	at com.sleepycat.je.rep.utilint.SizeAwaitMap.sizeAwait(SizeAwaitMap.java:106)
	at com.sleepycat.je.rep.impl.node.FeederManager.awaitFeederReplicaConnections(FeederManager.java:528)
	at com.sleepycat.je.rep.impl.node.DurabilityQuorum.ensureReplicasForCommit(DurabilityQuorum.java:74)
	at com.sleepycat.je.rep.impl.RepImpl.txnBeginHook(RepImpl.java:944)
	at com.sleepycat.je.rep.txn.MasterTxn.txnBeginHook(MasterTxn.java:158)
	at com.sleepycat.je.txn.Txn.initTxn(Txn.java:365)
	at com.sleepycat.je.txn.Txn.<init>(Txn.java:275)
	at com.sleepycat.je.txn.Txn.<init>(Txn.java:254)
	at com.sleepycat.je.rep.txn.MasterTxn.<init>(MasterTxn.java:114)
	at com.sleepycat.je.rep.txn.MasterTxn$1.create(MasterTxn.java:102)
	at com.sleepycat.je.rep.txn.MasterTxn.create(MasterTxn.java:380)
	at com.sleepycat.je.rep.impl.RepImpl.createRepUserTxn(RepImpl.java:924)
	at com.sleepycat.je.txn.Txn.createUserTxn(Txn.java:301)
	at com.sleepycat.je.txn.TxnManager.txnBegin(TxnManager.java:182)
	at com.sleepycat.je.dbi.EnvironmentImpl.txnBegin(EnvironmentImpl.java:2366)
	at com.sleepycat.je.Environment.beginTransactionInternal(Environment.java:1437)
	at com.sleepycat.je.Environment.beginTransaction(Environment.java:1319)
        ...
Caused by: java.lang.IllegalStateException: FeederManager shutdown
	at com.sleepycat.je.rep.impl.node.FeederManager.shutdownFeeders(FeederManager.java:498)
	at com.sleepycat.je.rep.impl.node.FeederManager.runFeeders(FeederManager.java:462)
	at com.sleepycat.je.rep.impl.node.RepNode.run(RepNode.java:1479)

[#23970] (6.3.0)

Fixed a bug that could cause a LOG_FILE_NOT_FOUND (log corruption) for workloads where eviction is heavy and databases are often opened and closed. [#24111] (6.3.0)

Improved performance for "small" data records by embedding "small" LNs in BINs.
Normally, records (key-value pairs) are stored on disk as individual byte sequences called LNs (leaf nodes) and they are accessed via a Btree. Specifically, the bottom layer nodes of the Btree (called BINs) contain an array of slots, where each slot represents an associated data record. Among other things, it stores the key of the record and the most recent disk address of that record. Records and BTree nodes share the disk space (are stored in the same kind of files), but LNs are stored separately from BINs, i.e., there is no clustering or co-location of a BIN and its child LNs.
With embedded LNs, a whole record may be stored inside a BIN (i.e., a BIN slot may contain both the key and the data portion of a record). A record will be "embedded" if the size (in bytes) of its data portion is less than or equal to the value of the new EnvironmentConfig.TREE_MAX_EMBEDDED_LN configuration parameter. The decision to embed a record or not is taken on a record-by-record basis. As a result, a BIN may contain both embedded and non-embedded records. The "embeddedness" of a record is a dynamic property: a size-changing update may turn a non-embedded record to an embedded one or vice-versa.
The performance trade-offs of embedding or not embedding records are described in the javadoc for the TREE_MAX_EMBEDDED_LN configuration parameter.
To exploit embedded LNs during disk ordered scans, a new "binsOnly" mode has been added in DiskOrderedCursorConfig. In this mode, only the BINs of a database will be accessed (not the LNs). As a result, the scan will be faster, but the data portion of a record will be returned only if the record is embedded. This is most useful when we expect that all the records in a database will be embedded.
Finally, a new statistic has been added to the PreloadStats class. It is the number of embedded LNs encountered during the preload() operation, and is accessible via the getNEmbeddedLNs() method.
[#21488] (6.3.0)

Two more changes were done as side-effects of the embedded LNs work described above.
First, we clarified the documented definition of partial comparators, although the actual behavior of partial comparators did not change. The documentation change is subtle and will only be interesting to those currently using the PartialComparator interface. See the PartialComparator javadoc for details.
The second change is a fix for a bug that could occur only if a PartialComparator was used (and as a result record keys were updatable). In this case and under some rare situations, updates done on keys could be lost.
[#21488] (6.3.0)

Cleaner utilization adjustments are no longer needed, and the following related APIs have been deprecated and will be removed completely in a future release. In addition, cleaner probes are no longer performed, since they were used only for utilization adjustments.
- EnvironmentConfig.CLEANER_ADJUST_UTILIZATION
- EnvironmentStats.getLNSizeCorrectionFactor
- EnvironmentStats.getNCleanerProbeRuns
In JE 6.0 the default value for CLEANER_ADJUST_UTILIZATION was changed to false, because the LN sizes it was adjusting were stored in the Btree in that release. Now in JE 6.3, setting CLEANER_ADJUST_UTILIZATION has no effect and the two stat getter methods always return zero.
[#24090] (6.3.0)

Added statistics that provide information about replication.
- ReplicatedEnvironmentStats.getLastCommitTimestamp
- ReplicatedEnvironmentStats.getLastCommitVLSN
- ReplicatedEnvironmentStats.getReplicaDelayMap
- ReplicatedEnvironmentStats.getReplicaLastCommitTimestampMap
- ReplicatedEnvironmentStats.getReplicaLastCommitVLSNMap
- ReplicatedEnvironmentStats.getReplicaVLSNLagMap
- ReplicatedEnvironmentStats.getReplicaVLSNRateMap
- ReplicatedEnvironmentStats.getVLSNRate
[#23896] (6.3.0)

Made several improvements to CacheMode behavior and CacheMode javadoc, and deprecated two CacheModes.
- The behavior of CacheMode.EVICT_BIN has changed. Previously, the BIN was evicted even when it was dirty. This means the BIN was logged if it was evicted by a write operation using this mode, or if it was dirty due to a previous write operation using any mode. Now, a dirty BIN will not be evicted by this mode, but in this case all LNs in the BIN will be evicted. This mode was changed in order to prevent BINs from being logged repeatedly due to the use of this mode. Logging should be deferred for as long as possible (ideally until the next checkpoint) in order to reduce writing costs and associated log cleaning costs.
- The behavior of CacheMode.UNCHANGED has also changed. We expect the UNCHANGED mode to be important for many applications, since it allows performing a full Database scan without displacing hot data in the cache. Previously, when a Btree node (LN or BIN) was loaded into cache by an operation with this cache mode, it was left in cache. This means that the cache was perturbed by operations using this mode, which is contrary to the intent of the mode. Even worse such nodes were made "hot" by the operation meaning that they would not be evicted soon. Now, when the node is loaded into cache by an operation with this cache mode, it is evicted from cache after the operation. An exception to this rule is that a dirty BIN will not be evicted and logged, for the same reasons stated above.
- Non-sticky cursors (see CursorConfig.setNonSticky) now work with all cache modes. Previously, CacheMode.EVICT_BIN and MAKE_COLD were incompatible with non-sticky cursors, because the implementation of BIN eviction was problematic with non-sticky cursors. This problem has been solved and these incompatibilities were removed, primarily so that CacheMode.UNCHANGED (which may also evict BINs) will work with non-sticky cursors.
- CacheMode.KEEP_HOT has been deprecated. In this release, its behavior is unchanged. In the next release it will behave as if CacheMode.DEFAULT were specified. The reasons for deprecating this mode are:
  1. The only potential benefit of KEEP_HOT, as compared to DEFAULT, is that KEEP_HOT attempts to keep the record's leaf-node (LN) and its containing bottom internal node (BIN) in cache even if it is not accessed frequently. We don't know of a use case for this behavior.
  2. There are currently implementation problems with KEEP_HOT. The current implementation of the cache evictor is based on an LRU list, and there is no practical way to keep all BINs accessed with KEEP_HOT at the hot end of the LRU list. The current implementation moves it to the hot end when it reaches the cold end (as other BINs are accessed and moved to the hot end), if the BIN has not been accessed since it was made "keep hot". But if the BIN again moves to the cold end, it is evicted to try to prevent the cache from overflowing when KEEP_HOT is used for many operations. This approach does not really guarantee that the cache won't overflow, and also does not really force the node to stay hot.
- CacheMode.MAKE_COLD has been deprecated. In this release, its behavior is unchanged. In the next release it will behave as if CacheMode.UNCHANGED were specified. The reasons for deprecating this mode are:
  1. MAKE_COLD was originally added in an attempt to avoid perturbing the cache for full Database scans, etc. The UNCHANGED mode should really be used for this purpose, especially given the improvements made to this mode (discussed above).
  2. The main difference between MAKE_COLD and the new behavior of UNCHANGED is that MAKE_COLD always evicts the LN and BIN, regardless of whether they have been made "hot" by other operations. Again, we don't know of a use case for this behavior.
- The javadoc for the CacheMode enumeration has been reworked to reflect the behavior changes described above. More information has also been added about the eviction process and the behavior and intended use of each cache mode.
[#24154] (6.3.2)

DbBackup.startBackup has been enhanced to make the use of the EnvironmentConfig.ENV_RECOVERY_FORCE_NEW_FILE unnecessary, except in special cases. See the "Restoring from a backup" section in the DbBackup javadoc for more information. [#22865] (6.3.4)

The Environment.cleanLogFile method has been added to allow cleaning a single file at a time. This is in contrast to Environment.cleanLog, which may clean a large number of files over a long time period. See the javadoc for cleanLog and cleanLogFile for details on the intended use cases and other information.
Also, the javadoc for Environment.close now talks about performing an extra checkpoint prior to calling close and disabling the cleaner threads. This is related to the "batch cleaning" process described in the cleanLogFile javadoc.
[#24181] (6.3.4)

Fixed a bug that can cause data log corruption, resulting in a failure in DbVerifyLog or during recovery under certain circumstances. The bug could occur when multiple threads are performing write operations concurrently. The corruption could go unnoticed unless DbVerifyLog is run, or the corrupt portion of the log happens to be processed by recovery. The latter is unlikely but possible. An example of the DbVerifyLog failure is below.
```
Caused by: com.sleepycat.je.util.LogVerificationException: Log is invalid,
fileName: 00038369.jdb fileNumber: 0x38369 logEntryOffset: 0x84
verifyState: INVALID reason: Header prevOffset=0x26 but prevEntryStart=0x45
```
[#24211] (6.3.4)

Fixed a bug that caused the following exception when setting the replication helper host/port parameter to an empty string.

Caused by: java.lang.IllegalArgumentException: Host and port pair was missing
    at com.sleepycat.je.rep.utilint.HostPortPair.getSocket(HostPortPair.java:29)
    at com.sleepycat.je.rep.utilint.HostPortPair.getSockets(HostPortPair.java:56)
    at com.sleepycat.je.rep.impl.RepImpl.getHelperSockets(RepImpl.java:1499)
    at com.sleepycat.je.rep.impl.node.RepNode.findMaster(RepNode.java:1214)
    at com.sleepycat.je.rep.impl.node.RepNode.startup(RepNode.java:787)
    at com.sleepycat.je.rep.impl.node.RepNode.joinGroup(RepNode.java:1988)
    at com.sleepycat.je.rep.impl.RepImpl.joinGroup(RepImpl.java:523)
    at com.sleepycat.je.rep.ReplicatedEnvironment.joinGroup(ReplicatedEnvironment.java:525)
    at com.sleepycat.je.rep.ReplicatedEnvironment.(ReplicatedEnvironment.java:587)
...

When an empty string is specified for the helper host/port, the parameter is not used by JE. [#24234] (6.3.6)

Fixed DPL bytecode enhancer so it works with Java 8-compiled classes. The DPL was working earlier with Java 8 in the sense that our Java 7-compiled libraries could be used from a Java 8 app. But the bytecode enhancer was failing when used to enhance a Java 8-compiled class. This was fixed by upgrading to ASM 5.0.3, which supports Java 8 bytecode. [#24225] (6.3.6)

Changes in 6.2.7

A cursor may now be optionally configured to be "non-sticky". This has certain performance advantages:
- Some processing is avoided because the prior position is not maintained.
- The lock on the record at the prior position is released before acquiring the lock on the record at the new position. This can help to prevent deadlocks in certain situations.
For more information, see the javadoc for CursorConfig.setNonSticky.
[#23775] (6.2.0)

Further exploitation of BIN-deltas for CRUD operations.
For backgroud and previous work in this area, see the changelog for the 6.1 release. In this release we have extended the set of CRUD operations that are performed in BIN-deltas, without the need to mutate them to full BINs (and thus saving the disk reads that would be required to fetch the full BINs in memory). Specifically, the following additional operations can now exploit BIN-deltas:
Insertions and updates, when no tree node splits are required and the key of the record to be inserted/updated is found in a BIN-delta.
Blind operations: we say that a record operation (insertion, update, or deletion) is performed "blindly" in a BIN-delta, when the delta does not contain a slot with the operation's key and we don't need to access the full BIN to check whether such a slot exists there or to extract any information from the full-BIN slot, if it exists. The condition that no tree node splits are required applies to blind operations as well. The following operations can be performed blindly: - Replay of insertions at replica nodes. - Insertions during recovery redo. - Updates and deletes during recovery redo, for databases with duplicates.
A new statistic has been added to count the number blind operations performed, including the blind put operations described below. This count can be obtained via the EnvironmentStats.getNBINDeltaBlindOps() method.
[#23680] (6.2.0)

Blind put operations in BIN-deltas.
Normally, blind puts are not possible: we need to know whether the put is actually an update or an insertion, i.e., whether the key exists in the full BIN or not. Furthermore, in case of update we also need to know the location of the previous record version to make the current update abortable. However, it is possible to answer at least the key existence question by adding a small amount of extra information in the deltas. If we do so, puts that are actual insertions can be done blindly.
To answer whether a key exists in a full BIN or not, each BIN-delta stores a bloom filter, which is a very compact, approximate representation of the set of keys in the full BIN. Bloom filters can answer set membership questions with no false negatives and very low probability of false positives. As a result, put operations that are actual insertions can almost always be performed blindly.
To make possible the blind puts optimization in JE databases that use custom BTree and/or duplicates comparators, these comparators must perform "binary equality", that is, they must consider two keys (byte arrays) to be equal if and only if they have the same length and they are equal byte-per-byte. To communicate to the JE engine that a comparator does binary equality, the comparator must implement the new BinaryEqualityComparator tag interface.
[#23768] (6.2.1)

Added LockMode.READ_UNCOMMITTED_ALL. When using this mode, unlike READ_UNCOMMITTED, deleted records will not be skipped by read operations when the deleting transaction is still open (and may later abort, in which case the record will no longer be deleted). See the LockMode javadoc for further details.
[#23660] (6.2.1)

Added two optimizations for secondary DB read operations.
- For secondary DB read operations where the primary record data is not requested (because DatabaseEntry.setPartial is called on the 'data' parameter), a Btree lookup and record lock of the primary record are no longer performed. This change does not impact the meaning of the isolation mode used for such secondary reads, i.e., the semantics are correct without acquiring a lock on the primary record.
- For secondary DB read operations where the primary record data is requested, one less record lock is now acquired. Previously, both the primary and secondary records were locked. Now, only the primary record is locked. This optimization does not apply to the serializable isolation mode. The optimization applies only to the read-committed and repeatable-read isolation modes, and does not impact the meaning of these modes, i.e., the semantics are correct without acquiring a lock on the secondary record.
[#23326] (6.2.2)

Fixed a bug that could cause the following Collections API and DPL methods to incorrectly return an empty result (no records).
- When using the DPL (com.sleepycat.persist) and calling EntityCursor.last() when the cursor was created with an end point (toKey parameter). Also when EntityCursor.prev() or prevNoDup() is called and the cursor is not initialized, since this is equivalent to calling last().
- When using the Collections API (com.sleepycat.collections) and calling SortedSet.last() or SortedMap.lastKey().
The problem occurs when searching for the last record in a key range, while another thread is concurrently inserting records near the end of the key range. An empty result is returned, regardless of the number of records in the key range.
[#23687] (6.2.2)

Fixed bugs in the computation of the nINCompactKey and nINNoTarget stats (EnvironmentStats.getNINCompactKeyIN and getNINNoTarget). Prior to the fixes, these stats would sometimes have negative values. [#23718] (6.2.3)

Fixed a bug that caused a DB to become unusable when it is removed or truncated (by calling Environment.removeDatabase or truncateDatabase) using a read-committed transaction, and the transaction aborts (explicitly, or due to a crash before commit). In this case the DB will not be accessible -- it cannot be opened, truncated or removed. When attempting to open the DB, an exception such as the following is thrown:

Exception in thread "main" com.sleepycat.je.DatabaseNotFoundException: (JE 6.1.5) Attempted to remove non-existent database ...
at com.sleepycat.je.dbi.DbTree.lockNameLN(DbTree.java:869)
at com.sleepycat.je.dbi.DbTree.doRemoveDb(DbTree.java:1130)
at com.sleepycat.je.dbi.DbTree.dbRemove(DbTree.java:1183)
at com.sleepycat.je.Environment$1.runWork(Environment.java:947)
at com.sleepycat.je.Environment$DbNameOperation.runOnce(Environment.java:1172)
at com.sleepycat.je.Environment$DbNameOperation.run(Environment.java:1155)
at com.sleepycat.je.Environment.removeDatabase(Environment.java:941)
...

A workaround for the problem in earlier releases is to avoid using read-committed for a transaction used to perform a DB remove or truncate operation.

[#23821] (6.2.3)

Fixed a bug that caused an exception during log cleaning, although it has been observed very rarely. It could also potentially cause data corruption, but this has never been reported or observed in tests. Examples of the exceptions that have been observed are below.

com.sleepycat.je.EnvironmentFailureException: Environment invalid because of
previous exception: (JE 6.1.0) ...
    at com.sleepycat.je.EnvironmentFailureException.unexpectedException(EnvironmentFailureException.java:315)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:477)
    at com.sleepycat.je.log.LogManager.logItems(LogManager.java:419)
    at com.sleepycat.je.log.LogManager.multiLog(LogManager.java:324)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:272)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:261)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:223)
    at com.sleepycat.je.dbi.EnvironmentImpl.rewriteMapTreeRoot(EnvironmentImpl.java:1285)
    at com.sleepycat.je.cleaner.FileProcessor.processFile(FileProcessor.java:701)
    at com.sleepycat.je.cleaner.FileProcessor.doClean(FileProcessor.java:274)
    at com.sleepycat.je.cleaner.FileProcessor.onWakeup(FileProcessor.java:137)
    at com.sleepycat.je.utilint.DaemonThread.run(DaemonThread.java:148)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 111
    at com.sleepycat.util.PackedInteger.writeInt(PackedInteger.java:188)
    at com.sleepycat.je.log.LogUtils.writePackedInt(LogUtils.java:155)
    at com.sleepycat.je.cleaner.DbFileSummary.writeToLog(DbFileSummary.java:79)
    at com.sleepycat.je.dbi.DatabaseImpl.writeToLog(DatabaseImpl.java:2410)
    at com.sleepycat.je.dbi.DbTree.writeToLog(DbTree.java:2050)
    at com.sleepycat.je.log.entry.SingleItemEntry.writeEntry(SingleItemEntry.java:114)
    at com.sleepycat.je.log.LogManager.marshallIntoBuffer(LogManager.java:745)
    at com.sleepycat.je.log.LogManager.serialLogWork(LogManager.java:611)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:461)
    ... 11 more

Another instance of the same problem with a slightly different stack trace is below:

java.nio.BufferOverflowException UNEXPECTED_EXCEPTION_FATAL: Unexpected
internal Exception, unable to continue. Environment is invalid and must be
closed.
    at com.sleepycat.je.EnvironmentFailureException.unexpectedException(EnvironmentFailureException.java:315)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:481)
    at com.sleepycat.je.log.LogManager.logItems(LogManager.java:423)
    at com.sleepycat.je.log.LogManager.multiLog(LogManager.java:325)
    at com.sleepycat.je.log.LogManager.log(LogManager.java:273)
    at com.sleepycat.je.tree.LN.logInternal(LN.java:600)
    at com.sleepycat.je.tree.LN.log(LN.java:411)
    at com.sleepycat.je.cleaner.FileProcessor.processFoundLN(FileProcessor.java:1070)
    at com.sleepycat.je.cleaner.FileProcessor.processLN(FileProcessor.java:884)
    at com.sleepycat.je.cleaner.FileProcessor.processFile(FileProcessor.java:673)
    at com.sleepycat.je.cleaner.FileProcessor.doClean(FileProcessor.java:278)
    at com.sleepycat.je.cleaner.FileProcessor.onWakeup(FileProcessor.java:137)
    at com.sleepycat.je.utilint.DaemonThread.run(DaemonThread.java:148)
Caused by: java.nio.BufferOverflowException
    at java.nio.HeapByteBuffer.put(HeapByteBuffer.java:189)
    at java.nio.ByteBuffer.put(ByteBuffer.java:859)
    at com.sleepycat.je.log.LogUtils.writeBytesNoLength(LogUtils.java:350)
    at com.sleepycat.je.log.entry.LNLogEntry.writeBaseLNEntry(LNLogEntry.java:371)
    at com.sleepycat.je.log.entry.LNLogEntry.writeEntry(LNLogEntry.java:333)
    at com.sleepycat.je.log.entry.BaseReplicableEntry.writeEntry(BaseReplicableEntry.java:48)
    at com.sleepycat.je.log.entry.LNLogEntry.writeEntry(LNLogEntry.java:52)
    at com.sleepycat.je.log.LogManager.marshallIntoBuffer(LogManager.java:751)
    at com.sleepycat.je.log.LogManager.serialLogWork(LogManager.java:617)
    at com.sleepycat.je.log.LogManager.serialLog(LogManager.java:465)

[#23492] (6.2.3)

Fixed a locking bug that causes a deadlock when no real deadlock exists. The bug shows up with cursors using read-committed isolation.
Here is the specific scenario:
1. Cursor C1 in thread T1 reads a record R using Transaction X1. C1 creates a ReadCommittedLocker L1, with X1 as its buddy. L1 locks R.
2. Cursor C2 in thread T2 tries to write-lock R, using another Transaction X2. X2 waits for L1 (T2 waits for T1).
3. Cursor C3 in thread T1 tries to read R using X1. C3 creates a ReadCommittedLocker L3, with X1 as its buddy. L3 tries to lock R. L1 and L3 are not recognized as buddies, so L3 waits for X2 (T1 waits for T2)
[#23821] (6.2.4)

The ant build (build.xml) has been updated so that the JUnit jar file is now downloaded from Maven Central when needed for running tests with the 'test' target. This jar is no longer needed for building a JE jar file with the 'jar' target. See installation.html for an updated description of how to build JE and run the unit tests. [#23669] (6.2.7)

Added EnvironmentConfig.CLEANER_USE_DELETED_DIR. This can be set to true when trying to reproduce and analyze LOG_FILE_NOT_FOUND problems. See the javadoc for details. More information was also added to the EnvironmentConfig.CLEANER_EXPUNGE javadoc on the same topic. [#23830] (6.2.8)

Added debugging information when an internal latch deadlock occurs due to a bug where a latch is not released. Note that latches are not user-visible entities and are unrelated to record locking. Latches are used internally for thread safety and only held for short durations. A latch deadlock is detected via a timeout mechanism. An EnvironmentFailureException is thrown in the thread that times out. Now, additionally a full thread dump is written to the je.info log at logging level SEVERE. The thread dump can be used to find the deadlock.
In addition, the EnvironmentConfig.ENV_LATCH_TIMEOUT parameter has been exposed to provide control over the timeout interval for atypical applications. This parameter has been present internally since latch timeouts were added in JE 6.0.3; however, the parameter was previously undocumented.
[#23897] (6.2.9)

Fixed two bugs having to do with lock conflicts. The two problems are distinct, but both occurred while creating a LockConflictException due to a lock timeout.

Fixed a bug that caused a ConcurrentModificationException when multiple lock tables are configured (EnvironmentConfig.LOCK_N_LOCK_TABLES). The exception was thrown when a lock conflict occurred along with particular concurrent activity in another thread that holds a lock. The methods in the stack trace when this problem occurs are:
```
      ...
      LockManager.findDeadlock1
      LockManager.findDeadlock
      LockManager.makeTimeoutMsgInternal
      ...
      
```

Fixed a bug that caused a thread deadlock, eventually stopping all threads accessing JE. This could happen when a lock conflict exception occurred while attempting to lock a record with read-committed isolation, and another thread (internal or external) also tried to lock the same record. An example of the two threads involved in the deadlock is below. Additional threads accessing JE methods are also likely to be blocked.

      "THREAD-USING-READ-COMMITTED":
        at com.sleepycat.je.txn.Txn.setState(Txn.java:2039)
        - waiting to lock <0x000000078953b720> (a com.sleepycat.je.txn.Txn)
        at com.sleepycat.je.txn.Txn.setOnlyAbortable(Txn.java:1887)
        at com.sleepycat.je.txn.BuddyLocker.setOnlyAbortable(BuddyLocker.java:158)
        at com.sleepycat.je.OperationFailureException.(OperationFailureException.java:200)
        at com.sleepycat.je.LockConflictException.(LockConflictException.java:135)
        at com.sleepycat.je.LockTimeoutException.(LockTimeoutException.java:48)
        at com.sleepycat.je.txn.LockManager.newLockTimeoutException(LockManager.java:665)
        at com.sleepycat.je.txn.LockManager.makeTimeoutMsgInternal(LockManager.java:623)
        at com.sleepycat.je.txn.SyncedLockManager.makeTimeoutMsg(SyncedLockManager.java:97)
        - locked <0x000000079068eaa8> (a com.sleepycat.je.latch.Latch)
        at com.sleepycat.je.txn.LockManager.lockInternal(LockManager.java:390)
        at com.sleepycat.je.txn.LockManager.lock(LockManager.java:276)
        ...
      "ANOTHER-THREAD-LOCKING-THE-SAME-RECORD":
        at com.sleepycat.je.txn.SyncedLockManager.attemptLock(SyncedLockManager.java:73)
        - waiting to lock <0x000000079068eaa8> (a com.sleepycat.je.latch.Latch)
        at com.sleepycat.je.txn.LockManager.lockInternal(LockManager.java:292)
        at com.sleepycat.je.txn.LockManager.lock(LockManager.java:276)
        - locked <0x000000078953b720> (a com.sleepycat.je.txn.Txn)
        ...

[#23894] (6.2.10)

Fixed a bug that could cause the following exception when calling Cursor.count, skipNext or skipPrev. The bug is likely to occur only when BINs (bottom internal nodes of the Btree) are frequently being evicted. Although the Environment is invalidated by this exception and must be closed, the problem is transient -- the Environment can be re-opened and no data loss or corruption will have occurred.

(JE 6.2.6) ... Latch not held: BIN17923 currentThread: ...  currentTime: ...
exclusiveOwner: -none- UNEXPECTED_STATE_FATAL: Unexpected internal state,
unable to continue. Environment is invalid and must be closed.
at com.sleepycat.je.EnvironmentFailureException.unexpectedState(EnvironmentFailureException.java:405)
at com.sleepycat.je.latch.LatchImpl.release(LatchImpl.java:109)
at com.sleepycat.je.tree.IN.releaseLatch(IN.java:519)
at com.sleepycat.je.dbi.CursorImpl.skipInternal(CursorImpl.java:2737)
at com.sleepycat.je.dbi.CursorImpl.skip(CursorImpl.java:2612)
at com.sleepycat.je.Cursor.countHandleDups(Cursor.java:4055)
at com.sleepycat.je.Cursor.countInternal(Cursor.java:4028)
at com.sleepycat.je.Cursor.count(Cursor.java:1804) at
...

The last line above is a call to Cursor.count. The same problem could happen if Cursor.skipNext or skipPrev is called, and only the last few lines of the stack trace above would be different.

[#23872] (6.2.25)

The HA Feeder output threads now batch network writes whenever possible to reduce the resource overheads associated with transmitting small network packets. These changes enhance replication performance; improvements in the range of 5% have been observed for write intensive workloads.
[#23274] (6.2.25)

Added new statistics to count the number of user (non-internal) CRUD operations that are performed entirely on BIN deltas.
[#23883] (6.2.25)

Fixed a bug where no exception was thrown when using ReplicaAckPolicy.ALL and performing a write transaction in a two node replication group, and the replica node was down/unresponsive. InsufficientAcksException is now thrown in this situation, as specified in the documentation. [#23934] (6.2.26)

Fixed a bug in the internal SortedLSNTreeWalker class, which is used to implement the Database.preload() and Environment.preload() methods. When these methods are called, the bug can lead to the creation of a corrupted BTree, and as a result, subsequent loss of data. The bug was introduced in JE 6.0.
[#23952] (6.2.27)

Added EntityIndex.getDatabase. [#23971] (6.2.27)

Fixed a bug where an assertion incorrectly fired during CRUD operations. This happened when there was concurrent activity in other threads that changed the number of records in the same portion of the Btree. An example stack trace is below.
```
java.lang.AssertionError
 at com.sleepycat.je.dbi.CursorImpl.getCurrentKey(CursorImpl.java:500)
 at com.sleepycat.je.dbi.CursorImpl.getCurrentKey(CursorImpl.java:483)
 at com.sleepycat.je.Cursor.dupsGetNextOrPrevDup(Cursor.java:2882)
 at com.sleepycat.je.Cursor.retrieveNextHandleDups(Cursor.java:2836)
 at com.sleepycat.je.Cursor.retrieveNext(Cursor.java:2816)
 at com.sleepycat.je.Cursor.getNextDup(Cursor.java:1150)
 [ app specific portion ... ]
```
In the stack trace above the Cursor.getNextDup method is being called. There are other operations where the same thing could happen. The common factor is the call to the internal CursorImpl.getCurrentKey method, which fires the assertion.
[#23971] (6.2.29)

Fixed a bug that prevents recovery, i.e., prevents the Environment from being opened. The bug has always been present in JE but has appeared in tests only recently, and has not been reported in the field. Deleting records in a large range of keys might make the bug more likely to occur. An example of the stack trace when the failure occurs is below:

com.sleepycat.je.EnvironmentFailureException: (JE 6.2.29) ... last
LSN=0x533/0x41f59 LOG_INTEGRITY: Log information is incorrect, problem is
likely persistent. Environment is invalid and must be closed.
        at com.sleepycat.je.recovery.RecoveryManager.traceAndThrowException(RecoveryManager.java:3031)
        at com.sleepycat.je.recovery.RecoveryManager.readINs(RecoveryManager.java:1010)
        at com.sleepycat.je.recovery.RecoveryManager.buildINs(RecoveryManager.java:804)
        at com.sleepycat.je.recovery.RecoveryManager.buildTree(RecoveryManager.java:717)
        at com.sleepycat.je.recovery.RecoveryManager.recover(RecoveryManager.java:352)
        at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(EnvironmentImpl.java:670)
        at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(DbEnvPool.java:208)
        at com.sleepycat.je.Environment.makeEnvironmentImpl(Environment.java:251)
        at com.sleepycat.je.Environment.(Environment.java:232)
        at com.sleepycat.je.Environment.(Environment.java:188)
        at com.sleepycat.je.rep.ReplicatedEnvironment.(ReplicatedEnvironment.java:573)
        at com.sleepycat.je.rep.ReplicatedEnvironment.(ReplicatedEnvironment.java:443)
        [ app specific portion ... ]
Caused by: com.sleepycat.je.EnvironmentFailureException: (JE 6.2.29) ...
fetchIN of 0x35c/0x3f7f9 parent IN=11688 IN class=com.sleepycat.je.tree.IN
lastFullVersion=0x533/0x5d47d lastLoggedVersion=0x533/0x5d47d
parent.getDirty()=false state=0 LOG_FILE_NOT_FOUND: Log file missing, log is
likely invalid. Environment is invalid and must be closed.
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1866)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1764)
        at com.sleepycat.je.tree.Tree.getParentINForChildIN(Tree.java:1346)
        at com.sleepycat.je.recovery.RecoveryManager.recoverChildIN(RecoveryManager.java:2025)
        at com.sleepycat.je.recovery.RecoveryManager.recoverIN(RecoveryManager.java:1834)
        at com.sleepycat.je.recovery.RecoveryManager.replayOneIN(RecoveryManager.java:1099)
        at com.sleepycat.je.recovery.RecoveryManager.readINs(RecoveryManager.java:988)
        ... 16 more
Caused by: java.io.FileNotFoundException: .../0000035c.jdb (No such file or directory)
        at java.io.RandomAccessFile.open(Native Method)
        at java.io.RandomAccessFile.(RandomAccessFile.java:241)
        at java.io.RandomAccessFile.(RandomAccessFile.java:122)
        at com.sleepycat.je.log.FileManager$DefaultRandomAccessFile.(FileManager.java:3260)
        at com.sleepycat.je.log.FileManager$6.createFile(FileManager.java:3288)
        at com.sleepycat.je.log.FileManager.openFileHandle(FileManager.java:1311)
        at com.sleepycat.je.log.FileManager.getFileHandle(FileManager.java:1183)
        at com.sleepycat.je.log.LogManager.getLogSource(LogManager.java:1135)
        at com.sleepycat.je.log.LogManager.getLogEntry(LogManager.java:822)
        at com.sleepycat.je.log.LogManager.getLogEntryAllowInvisibleAtRecovery(LogManager.java:787)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1801)
        ... 22 more

[#23990] (6.2.31)

Fixed a bug that can cause data log corruption. This has been reported only as a rare occurrence, but could impact any application where not all Btree internal nodes fit in cache. An example stack trace is below, although other stack traces could also apply where an IN (internal node) is being fetched.

com.sleepycat.je.EnvironmentFailureException: (JE 6.2.9) ...
fetchIN of 0x10cbc/0x696373 parent IN=84363 IN
class=com.sleepycat.je.tree.IN lastFullVersion=0x10e00/0x82006e
lastLoggedVersion=0x10e00/0x82006e parent.getDirty()=false state=0
LOG_FILE_NOT_FOUND: Log file missing, log is likely invalid. Environment is
invalid and must be closed.
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1866)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1752)
        at com.sleepycat.je.tree.Tree.search(Tree.java:2293)
        at com.sleepycat.je.tree.Tree.search(Tree.java:2193)
        at com.sleepycat.je.tree.Tree.getParentBINForChildLN(Tree.java:1481)
        at com.sleepycat.je.cleaner.FileProcessor.processLN(FileProcessor.java:836)
        ... 5 more
Caused by: java.io.FileNotFoundException: /local/pyrox/DS2/asinst_1/OUD/db/Europe/00010cbc.jdb (No such file or directory)
        at java.io.RandomAccessFile.open(Native Method)
        at java.io.RandomAccessFile.(RandomAccessFile.java:241)
        at java.io.RandomAccessFile.(RandomAccessFile.java:122)
        at com.sleepycat.je.log.FileManager$DefaultRandomAccessFile.(FileManager.java:3208)
        at com.sleepycat.je.log.FileManager$6.createFile(FileManager.java:3236)
        at com.sleepycat.je.log.FileManager.openFileHandle(FileManager.java:1305)
        at com.sleepycat.je.log.FileManager.getFileHandle(FileManager.java:1177)
        at com.sleepycat.je.log.LogManager.getLogSource(LogManager.java:1151)
        at com.sleepycat.je.log.LogManager.getLogEntry(LogManager.java:843)
        at com.sleepycat.je.log.LogManager.getLogEntryAllowInvisibleAtRecovery(LogManager.java:808)
        at com.sleepycat.je.tree.IN.fetchINWithNoLatch(IN.java:1801)
        ... 10 more

[#24046] (6.2.31)

Fixed a bug that can cause data log corruption when using a deferred-write database. In the one reported instance of the problem, missing records were reported. A corruption (e.g., LOG_FILE_NOT_FOUND) is also posssible. [#24066] (6.2.31)

Changes in 6.1.5

Made an improvement to eviction for Oracle NoSQL DB users, and several improvements to the DbCacheSize utility.
For Oracle NoSQL DB users only, record versions are now discarded using a separate eviction step. This means that the record versions can be discarded to free cache memory without discarding the entire BIN (bottom internal node). In general, this makes better use of memory and reduces IO for some workloads.
The improvements to DbCacheSize are as follows.
- When -je.rep.preserveRecordVersion true is passed on the command line, more information is output by the utility. See the new Record Versions and Oracle NoSQL Database section of the DbCache javadoc for more information.
- The minimum and maximum cache sizes are no longer output. Previously, the difference between these values was only due to an optimization that applied to small log files. This optimization is now accounted for only when the file size is small enough to allow for it. Be sure to pass -je.log.fileMax LENGTH on the command line as described in the javadoc.
- The -outputproperties switch now outputs internalNodes, internalNodesAndVersions, and allNodes, corresponding to the changes above. The older minInternalNodes/maxInternalNodes and minAllNodes/maxAllNodes values are still output but deprecated, and the min and max values in each pair are equal.
- The output has been simplified by removing the internal Btree information. Btree information can optionally be output using the new -btreeinfo switch.
[#23550] (6.1.0)

Fixes a bug which prevented serialization of ReplicaWriteException. Previously an attempt to serialize this exception could fail with the following characteristic stack trace when the StateChangeEvent object was encountered during serialization:

 Caused by: java.io.NotSerializableException: com.sleepycat.je.rep.StateChangeEvent

    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1181)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1541)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1506)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1429)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1175)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1541)
    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:439)
    at java.util.logging.LogRecord.writeObject(LogRecord.java:470)
    ...

[#23578] (6.1.1)

The JE HA replica replay mechanism now uses a separate thread to write replica acknowledgements and heartbeat responses to the network. This change results in two improvements:
1. The replay of changes sent by the master can make progress even in the presence of brief network stalls, thus increasing replica replay throughput; improvements in the range of 5 to 10% have been observed in internal test scenarios.
2. This new thread is also used to send spontaneous heartbeat response messages, making the heartbeat mechanism, used to detect node failures, more robust.
[#23195] (6.1.1)

Performance enhancement: executing a subset of CRUD and internal operations on memory-resident BIN-deltas.
Before JE 6.0, BIN-deltas were used as a disk optimization only: to reduce the amount of bytes written to disk every time a new BIN version had to to be logged. BIN-deltas would never appear in the in-memory BTrees, and if the most recently logged version of a BIN was a delta, fetching that BIN into the in-memory tree required 2 disk reads: one for the delta and one for the most recent full-BIN version.
Starting with JE 6.0, BIN-deltas can appear in the in-memory BTree. Specifically, if a full dirty BIN is selected for eviction, rather than evicting the whole BIN (and incurring a disk write), the BIN is converted to a delta that stays in the cache. If a subsequent operation needs the full BIN and the delta is still in the cache, only one disk read will be done.
Further disk-read savings can be realized, because many operations can (under certain conditions) be performed directly on the BIN-delta, without the need for the full BIN. However, in 6.0, only a small subset of background operations were modified to exploit BIN-deltas. In JE 6.1, the set of operations that can be performed on BIN-deltas has been extended. Examples of such operations include key searches in BTrees, if the search key is found on a BIN delta and deletion or update of the record a cursor is located on, if the cursor is located on a BIN-delta. These changes affect both internal operations as well as the search, delete, and putCurrent methods of the Database and Cursor API classes.
[#23428] (6.1.1)

Performance enhancement: Reduced latch contention during BTree searches.
Typically, thread synchronization during BTree searches is done via latch coupling: at most 2 tree nodes (a parent and a child) are latched at a time. Furthermore, a node is latched in shared (SH) mode, unless it is expected that it will be updated, in which case it is latched in exclusive (EX) mode. Finally, SH latches are not upgradeable to EX latches (to avoid deadlocks and reduce latching overhead).
JE follows this general latch-coupling technique. However, it also has to deal with the JE-specific fact that fetching a missing child node into the cache requires that its memory-resident parent be updated (because the parent points to its children via direct Java object references). As a result, during a JE BTree search every node is potentially updated, which precludes the use of SH latches. To cope with this complication, JE has been using one of the following approaches during its various kinds of BTree searches: (a) use SH latches, but if a missing child needs to be fetched, release the SH latch on the parent and restart the search from the beginning, using EX latches on all nodes this time, (b) do grandparent latching: use SH latches but keep a latch on the grandparent node so that if we need to fetch a missing child of the parent node, the SH latch on the parent can be released, and then the parent can be relatched in EX mode, (c) do latch-coupling with EX latches only. Obviously, (c) is the worst choice, but all of the 3 approaches result in more and longer-held EX latches than necessary. As a result, some JE applications have experienced performance problems due to excessive latch contention during BTree searches.
In JE 6.1, a new latching algorithm has been implemented to replace all of (a), (b), and (c) above. The new algorithm uses SH latches, but if a missing child needs to be fetched, it first "pins" the parent (to prevent its eviction), then releases the SH latch on the parent, and finally reads the child node from the log (without any latches held). After the child is fetched, it latches the remembered parent in EX mode, unpins it, and checks whether it is still the correct parent for the search and for the child node that was fetched. If so, the search continues down the tree. If not, it restarts the search from the beginning. Compared to approach (a) above, this new algorithm may restart a search multiple times, however the probability of even a single restart is less than (a), and each restart uses SH latches. Furthermore, no latches are held during the long random disk read done to fetch a missing child.
[#18617] (6.1.1)

Fixed a bug that could result in the following exception in a JE HA application:

com.sleepycat.je.EnvironmentFailureException: 
 Node5(5):... VLSN 3,182,883 should be held within this tracker.

com.sleepycat.je.EnvironmentFailureException: 
 Node5(5):...end of last bucket should match end of range ...

[#23491]

Improved the Monitor's ability to discover group status changes, which should improve the robustness of notifications after the monitor is down or when it has lost network connectivity.
[#23631] (6.1.2)

A new implementation for Database.count() and a new variant of Database.count() that takes a memoryLimit as input.
Counting the number of records in a database is now implemented using a disk-ordered-scan (DOS), similar to the one used by DiskOrderedCursor. DOS may consume a large amount of memory, and to avoid OutOfMemoryErrors, it requires that a limit on its memory consumption is provided. As a result, a new method, Database.count(long memoryLimit), has been implemented that takes this memory limit as a parameter. The existing Database.count() method is still available and uses an internally established limit.
This change fixes two problems of the previous implementation (based on the SortedLSNTreeWalker class): 1. There was no upper bound on the memory consumption of the previous implementation and 2. It was buggy in the case where concurrent thread activity could cause full BINs to be mutated to deltas or vice versa.
[#23646] (6.1.2)

Fixed bug in DiskOrderedCursor.
Iterating over the records of a database via a DiskOrderedCursor would cause a crash if a BIN delta was encountered in the in-memory BTree (because in this case a copy of the BIN delta was created and cached for later use, but the copy did not contain all the needed information from the original). This bug was introduced in JE 6.0.11.
[#23646] (6.1.2)

Fixed a bug in DiskOrderedCursor for DeferredWrite databases. An example of the stack trace when the bug occurs is below. Note that although the exception message indicates that a file is missing, actually the problem was transient and no file was missing. Upgrading to the current JE release will fix the problem without requiring data conversion or restoring from a backup.

com.sleepycat.je.EnvironmentFailureException:
(JE 5.0.97) Environment must be closed, caused by:
com.sleepycat.je.EnvironmentFailureException:
Environment invalid because of previous exception:
(JE 5.0.97) ... java.io.FileNotFoundException: ...\ffffffff.jdb
(The system cannot find the file specified) LOG_FILE_NOT_FOUND:
Log file missing, log is likely invalid.
Environment is invalid and must be closed.
    at com.sleepycat.je.EnvironmentFailureException.wrapSelf(EnvironmentFailureException.java:210)
    at com.sleepycat.je.dbi.EnvironmentImpl.checkIfInvalid(EnvironmentImpl.java:1594)
    at com.sleepycat.je.dbi.DiskOrderedCursorImpl.checkEnv(DiskOrderedCursorImpl.java:234)
    at com.sleepycat.je.DiskOrderedCursor.checkState(DiskOrderedCursor.java:367)
    at com.sleepycat.je.DiskOrderedCursor.getNext(DiskOrderedCursor.java:324)
    ...

[#23676] (6.1.3)

An API change requires application changes if write operations are performed on a non-replicated database in a replicated environment. A code change is necessary for applications with the following characteristics:
- A ReplicatedEnvironment is used.
- A non-replicated, transactional Database is accessed (DatabaseConfig.setReplicated(false) and setTransactional(true) are called) in this environment.
- When writing to this database, an explicit (non-null) Transaction is specified.
In order to perform write operations in such cases, the application must now call TransactionConfig.setLocalWrite(true).
In addition, it is no longer possible to use a single transaction to write to both a replicated and a non-replicated databases. IllegalOperationException will be thrown if this is attempted.
These changes were necessary to prevent corruption when a transaction contains write operations for both replicated and non-replicated databases, and a failover occurs that causes a rollback of this transaction. The probability of corruption is low, but it can occur under the right conditions.
For more information see the javadoc for TransactionConfig.setLocalWrite(true), and the "Non-replicated Databases in a Replicated Environment" section of the ReplicatedEnvironment class javadoc.
[#23330] (6.1.3)

Read-only transactions are now supported. A read-only transaction prohibits write operations, and more importantly in a replicated environment it automatically uses Durability.ReplicaAckPolicy.NONE. A read-only transaction on a Master will thus not be held up, or throw InsufficientReplicasException, if the Master is not in contact with a sufficient number of Replicas at the time the transaction is initiated. To configure a read-only transaction, call TransactionConfig.setReadOnly(true). See this method's javadoc for more information.
Durability.READ_ONLY_TXN has been deprecated and TransactionConfig.setReadOnly should be used instead.
[#23330] (6.1.3)

Fixed a bug that could cause a NullPointerException, such as the one below, when a ReplicatedEnvironment is opened on an HA replica node. This prevents the environment from being opened.

The conditions that cause the bug are:

a replica has been restarted after an abnormal shutdown (ReplicatedEnvironment.close was not called),
a transaction writing records in multiple databases was in progress at the time of the abnormal shutdown,
one of the databases, but not all of them, is then removed or truncated, and finally
another abnormal shutdown occurs.

If this bug is encountered, it can be corrected by upgrading to the JE release containing this fix, and no data loss will occur.

This bug is similar to another bug that was fixed in JE 5.0.70 [#22052]. This bug differs in that the transaction must write records in multiple databases, and at least one but not all of the databases must be removed or truncated between the two abnormal shutdowns.

com.sleepycat.je.EnvironmentFailureException: (JE 6.1.3) Node1(-1):...
last LSN=0x3/0x4427 LOG_INTEGRITY: Log information is incorrect, problem is
likely persistent. Environment is invalid and must be closed.
    at com.sleepycat.je.recovery.RecoveryManager.traceAndThrowException(RecoveryManager.java:3012)
    at com.sleepycat.je.recovery.RecoveryManager.undoLNs(RecoveryManager.java:1253)
    at com.sleepycat.je.recovery.RecoveryManager.buildTree(RecoveryManager.java:741)
    at com.sleepycat.je.recovery.RecoveryManager.recover(RecoveryManager.java:352)
    at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(EnvironmentImpl.java:654)
    at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(DbEnvPool.java:208)
    at com.sleepycat.je.Environment.makeEnvironmentImpl(Environment.java:252)
    at com.sleepycat.je.Environment.(Environment.java:232)
    at com.sleepycat.je.Environment.(Environment.java:188)
    at com.sleepycat.je.rep.ReplicatedEnvironment.(ReplicatedEnvironment.java:573)
    at com.sleepycat.je.rep.ReplicatedEnvironment.(ReplicatedEnvironment.java:443)
    ... [app creates a new ReplicatedEnvironment here] ...
Caused by: java.lang.NullPointerException
    at com.sleepycat.je.log.entry.LNLogEntry.postFetchInit(LNLogEntry.java:412)
    at com.sleepycat.je.txn.TxnChain.(TxnChain.java:133)
    at com.sleepycat.je.txn.TxnChain.(TxnChain.java:84)
    at com.sleepycat.je.recovery.RollbackTracker$RollbackPeriod.getChain(RollbackTracker.java:1009)
    at com.sleepycat.je.recovery.RollbackTracker$Scanner.rollback(RollbackTracker.java:483)
    at com.sleepycat.je.recovery.RecoveryManager.undoLNs(RecoveryManager.java:1182)
    ... 11 more

[#22071] (6.1.3)

Fixed a bug where a transaction configured for no-wait (using TransactionConfig.setNoWait(true)) behaved as a normal (wait) transction when the ReadCommitted isolation mode was also used. Due to this bug, a LockTimeoutException was thrown when a LockNotAvailableException should have been thrown instead, and the transaction was invalidated when it should not have been. [#23653] (6.1.4)

Fixed eviction bug for shared-cache environments. The bug caused LRU corruption and potential memory leaks in certain cases. The bug was introduced in JE 6.0. Note that the bug has no impact for environments that are not using a shared cache (EnvironmentConfig.setSharedCache(true)). [#23696] (6.1.4)

Changes in 6.0.11

Added support in JE HA for the new SECONDARY node type. SECONDARY nodes can only be replicas, not masters, and do not participate in either elections or durability decisions. SECONDARY nodes can be used to increase the available number of read replicas without changing the election or durability quorum of the group, and without requiring communication with the secondaries during master elections or transaction commits.
Changes include adding the NodeType.SECONDARY enumeration constant, and the ReplicationGroup.getSecondaryNodes and ReplicationGroup.getDataNodes methods. [#22482] (6.0.1)

Made improvements to internal latching to allow interrupting threads that are waiting on latches, cause a timeouts when a latch deadlock occurs, and enable latch instrumentation via system properties. Note that latching is not related to transactional locking and latches are intended to be held for very short periods.
- When a JE thread is waiting on an internal latch, for example, when accessing Btree internal nodes, log buffers, etc, interrupting the thread is now possible and will result in a ThreadInterruptedException. In earlier versions, latching calls were not interruptible and a latch deadlock would require a process restart.
- When a JE thread is waiting on an internal latch, a timeout will occur if the latch cannot be acquired after 5 minutes and a fatal EnvironmentFailureException will be thrown. The timeout is intended to detect latch deadlocks earlier.
- A system property, JE_TEST, may be defined to true (-DJE_TEST=true) to enable JE debug/test instrumentation. Currently, this only adds latch tracking so that an internal latching error will contain more information about the problem. Over time, more JE instrumentation will be enabled via this switch. The JE_TEST property is set to true automatically when running the JE unit test suite via ant. This instrumentation is not intended for production use. Note that in earlier versions, however, this instrumentation was enabled when Java assertions (-ea) were enabled.
- An additional system property, JE_CAPTURE_LATCH_OWNER, may be set to true to capture the stack trace at the point that each latch is acquired exclusively. This additional information will appear in latching error messages and may help in debugging an internal latching problem. It is fairly expensive to capture the stack trace, and this switch should not be set in production.
- An undocumented EnvironmentConfig parameter, je.env.sharedLatches, is no longer used and silently ignored. Latches are now shared (read-write), rather than exclusive, whenever possible.
[#22993] (6.0.3)

The following log cleaner configuration parameters in the EnvironmentConfig class have been deprecated and are no longer used. If configured, they will be silently ignored. Lazy and proactive migration are no longer supported due to negative impacts on eviction, checkpointing and Btree splits. If a persistent log cleaner backlog occurs, the recommended solution is to configure additional cleaner threads.
- CLEANER_LAZY_MIGRATION
- CLEANER_BACKGROUND_PROACTIVE_MIGRATION
- CLEANER_FOREGROUND_PROACTIVE_MIGRATION
[#23070] (6.0.3)

When using secondary databases and DPL secondary indexes, the locking order for reads via a secondary has been changed to reduce the possibility of deadlocks. This optimization does not apply when the serializable isolation mode is used, and does not apply to the JoinCursor. [#22368] (6.0.4)

Improved Btree cache usage by caching a BIN-delta -- the partial form of a BIN containing only the dirty entries -- in preference to logging it and then evicting the entire BIN. This reduces disk reads if CRUD operations are performed on the BIN before the entire BIN is evicted, because only one BIN fetch rather than two is needed. Disk writes are also reduced to some degree. The performance improvement applies only when BINs are being evicted from cache. The improvement is signficant when CRUD operations address a non-random subset of the keys in the data set.
As part of the performance improvement work, the following statistics were added.
- nCachedBINDeltas: EnvironmentStats.getNCachedBINDeltas -- Number of BIN-deltas (partial BINs) in cache.
- nBINDeltasFetchMiss: EnvironmentStats.getNBINDeltasFetchMiss -- Number of BIN-deltas fetched to satisfy btree operations.
- nBINsMutated: EnvironmentStats.getNBINsMutated -- The number of BINs mutated to BIN-deltas by eviction.
- lastCheckpointInterval: EnvironmentStats.getLastCheckpointInterval -- Byte length from last checkpoint start to the previous checkpoint start.
In addition, the EnvironmentConfig.TREE_MAX_DELTA param has been deprecated. As of JE 5.0, the benefit from logging BIN-deltas is unrelated to the number of deltas that have been logged since the last full BIN. To configure BIN-delta logging, use EnvironmentConfig.TREE_BIN_DELTA.
[#22662] (6.0.5)

An optimization for Databases with sorted duplicates configured has been made to improve log cleaning performance. Records in duplicates databases need no longer be tracked or processed by the log cleaner, which reduces cleaning costs significantly when duplicates databases are used for a significant portion of a data set, for example, as secondary index databases.
As described under 'Upgrading from JE 5.0 or earlier' at the top of this document, to support this cleaner optimization a change was made involving partial Btree and duplicate comparators. Partial comparators are an advanced feature that few applications use. As of JE 6.0, using partial comparators is not recommended. Applications that do use partial comparators must now change their comparator classes to implement the new PartialComparator tag interface, before running the application with JE 6. Failure to do so may cause incorrect behavior during transaction aborts. See the PartialComparator javadoc for more information.
[#22864] (6.0.5)

Fixed a bug that sometimes resulted in an uncommitted record deletion performed in one transaction to be visible (result in a NOTFOUND result) to an operation performed in another transaction. This bug applies to the use of Database.delete and PrimaryIndex.delete. It does not apply to the use of SecondaryDatabase.delete, SecondaryIndex.delete, or the use of a cursor to perform a deletion. Note that this problem is distinct from a similar bug that was fixed in JE 5.0.98 ([#22892]).
[#23132] (6.0.5)

Modified the algorithm that protects cleaned log files from deletion to consider the relative cost of replication replay versus network restore, as well as available disk space. When JE HA decides whether to delete cleaned log files, it uses information it stores about the progress of replication replay for each electable replica to retain useful log files even if the replicas are offline, subject to the ReplicationConfig.REP_STREAM_TIMEOUT parameter. The system does not store information about replication progress for secondary replicas, though, so a different approach has been added.
The modified algorithm estimates the costs of replication replay and network restore, and protects log files from deletion that could be used for replay if there is sufficient disk space and replay would be less expensive than network restore. These computations apply to all replicas, but are particularly useful for secondary replicas, for which log files will not otherwise be retained if the replicas become temporarily unreachable. Note that disk space calculations are only performed when running with Java 7 or later.
Two new ReplicationConfig parameters were added:
- REPLAY_COST_PERCENT - The cost of replaying the replication stream as compared to the cost of performing a network restore.
- REPLAY_FREE_DISK_PERCENT - The target amount of free disk space to maintain when selecting log files to retain for use in replay.
[#22575] (6.0.5)

An improvement was made to the calculation of log utilization to avoid under-cleaning or over-cleaning. For example, when log utilization was estimated to be lower than actual utilization, unnecessary over-cleaning would occur, which could reduce performance. Or when log utilization was estimated to be higher than actual utilization, under-cleaning would prevent reclaiming unused disk space.
To prevent these problems, the size of each logged record is now stored in the Btree BINs (bottom internal nodes), so that utilization can be calculated correctly during record updates and deletions, while still avoiding a fetch of the old version of the record. With this change, the utilization adjustment facility in the log cleaner, which attempted to compensate for this problem by estimating utilization, is no longer needed by most applications.
Therefore the EnvironmentConfig.CLEANER_ADJUST_UTILIZATION parameter is now false by default rather than true, and will be disabled completely in a future version of JE. For more information, see the javadoc for this parameter.
[#22275] (6.0.7)

The helper hosts parameter used in JE HA replication is now mutable. Accordingly, the set/getHelperHosts() methods and the HELPER_HOST definition in com.sleepycat.je.rep.ReplicationConfig have been moved to their parent class, ReplicationMutableConfig. The change is fully link and source compatible. [#22753] (6.0.7)

Improved the performance of eviction by removing a bottleneck that was causing thread contention. Previously, for workloads with heavy eviction, threads were often waiting on a mutex in the TargetSelector.selectIN method. This impacted not only JE's dedicated background threads, but also application threads that were participating in critical eviction. A new approach is used that dramatically reduces thread contention and increases performance (compared to JE 5 and earlier) for such workloads.
In addition, the new eviction approach implements a more accurate LRU which ensures that dirty nodes are evicted last and thereby reduces unnecessary logging.
As part of this change, the following configuration parameters were deprecated and are ignored by JE:
```
    EnvironmentConfig.EVICTOR_NODES_PER_SCAN
    EnvironmentConfig.EVICTOR_LRU_ONLY
```
And the following configuration parameter was added:
```
    EnvironmentConfig.EVICTOR_N_LRU_LISTS
```
[#23063] (6.0.7)

A change was made involving the charset for internal text (messages) that appear in the JE log (.jdb files). Previously, the default JVM charset was used. When dumping the log with DbPrintLog (e.g., for debugging purposes), if the default JVM charset was different than the one at the time the log was written, the text messages would be garbled. For example, this occurred when the log was written with an EBCDIC charset and then dumped with a UTF8 charset. This has been fixed by always writing and reading text in the UTF8 charset. [#15296] (6.0.8)

A new HA configuration parameter: com.sleepycat.je.rep.ReplicationConfig.BIND_INADDR_ANY was added. This parameter permits binding of the port used by HA to all the local interfaces on the host. The javadoc associated with this configuration parameter provides further details. [#23437] (6.0.9)

Fix a bug that could under rare conditions, primarily frequent failovers, cause the following exception in an HA environment.

Caused by: com.sleepycat.je.EnvironmentFailureException: (JE 5.0.97)
node2(2):foo\node2 Read invisible log entry at 0x0/0xcb776
hdr type="INS_LN_TX/8" vlsn v="19,373" isReplicated="1" isInvisible="1"
prev="0xcb74c" size="17" cksum="2626620732"
LOG_INTEGRITY: Log information is incorrect, problem is likely persistent.
fetchTarget of 0x0/0xcb776 parent IN=29 IN class=com.sleepycat.je.tree.BIN
lastFullVersion=0x0/0xf154c lastLoggedVersion=0x0/0xf588e
parent.getDirty()=true state=3
at com.sleepycat.je.log.LogManager.getLogEntryFromLogSource(LogManager.java:1054)
at com.sleepycat.je.log.LogManager.getLogEntry(LogManager.java:906)
at com.sleepycat.je.log.LogManager.getLogEntryAllowInvisibleAtRecovery(LogManager.java:867)
at com.sleepycat.je.tree.IN.fetchTarget(IN.java:1427)
at com.sleepycat.je.tree.BIN.fetchTarget(BIN.java:1250)
at com.sleepycat.je.recovery.RecoveryManager.undo(RecoveryManager.java:2415)
at com.sleepycat.je.recovery.RecoveryManager.rollbackUndo(RecoveryManager.java:2268)
...

[#22848] (6.0.10)

EntityStore.close has been changed to fix a bug that caused a memory leak when the Database could not be closed, for example, if it had open cursors. The javadoc for this method was also updated to warn that it must be called to avoid memory leaks, even when the Environment is invalid. [#23462] (6.0.10)