724 lines
33 KiB
HTML
724 lines
33 KiB
HTML
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<!-- NewPage -->
|
||
|
|
<html lang="en">
|
||
|
|
<head>
|
||
|
|
<!-- Generated by javadoc (1.8.0_151) on Tue Oct 31 17:36:45 EDT 2017 -->
|
||
|
|
<title>CacheMode (Oracle - Berkeley DB Java Edition API)</title>
|
||
|
|
<meta name="date" content="2017-10-31">
|
||
|
|
<link rel="stylesheet" type="text/css" href="../../../style.css" title="Style">
|
||
|
|
<script type="text/javascript" src="../../../script.js"></script>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<script type="text/javascript"><!--
|
||
|
|
try {
|
||
|
|
if (location.href.indexOf('is-external=true') == -1) {
|
||
|
|
parent.document.title="CacheMode (Oracle - Berkeley DB Java Edition API)";
|
||
|
|
}
|
||
|
|
}
|
||
|
|
catch(err) {
|
||
|
|
}
|
||
|
|
//-->
|
||
|
|
var methods = {"i0":9,"i1":9};
|
||
|
|
var tabs = {65535:["t0","All Methods"],1:["t1","Static Methods"],8:["t4","Concrete Methods"]};
|
||
|
|
var altColor = "altColor";
|
||
|
|
var rowColor = "rowColor";
|
||
|
|
var tableTab = "tableTab";
|
||
|
|
var activeTableTab = "activeTableTab";
|
||
|
|
</script>
|
||
|
|
<noscript>
|
||
|
|
<div>JavaScript is disabled on your browser.</div>
|
||
|
|
</noscript>
|
||
|
|
<!-- ========= START OF TOP NAVBAR ======= -->
|
||
|
|
<div class="topNav"><a name="navbar.top">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<div class="skipNav"><a href="#skip.navbar.top" title="Skip navigation links">Skip navigation links</a></div>
|
||
|
|
<a name="navbar.top.firstrow">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="navList" title="Navigation">
|
||
|
|
<li><a href="../../../overview-summary.html">Overview</a></li>
|
||
|
|
<li><a href="package-summary.html">Package</a></li>
|
||
|
|
<li class="navBarCell1Rev">Class</li>
|
||
|
|
<li><a href="class-use/CacheMode.html">Use</a></li>
|
||
|
|
<li><a href="package-tree.html">Tree</a></li>
|
||
|
|
<li><a href="../../../deprecated-list.html">Deprecated</a></li>
|
||
|
|
<li><a href="../../../index-all.html">Index</a></li>
|
||
|
|
<li><a href="../../../help-doc.html">Help</a></li>
|
||
|
|
</ul>
|
||
|
|
<div class="aboutLanguage"><b>Berkeley DB Java Edition</b><br><font size=\"-1\"> version 7.5.11</font>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="subNav">
|
||
|
|
<ul class="navList">
|
||
|
|
<li><a href="../../../com/sleepycat/je/BtreeStats.html" title="class in com.sleepycat.je"><span class="typeNameLink">Prev Class</span></a></li>
|
||
|
|
<li><a href="../../../com/sleepycat/je/CheckpointConfig.html" title="class in com.sleepycat.je"><span class="typeNameLink">Next Class</span></a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="navList">
|
||
|
|
<li><a href="../../../index.html?com/sleepycat/je/CacheMode.html" target="_top">Frames</a></li>
|
||
|
|
<li><a href="CacheMode.html" target="_top">No Frames</a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="navList" id="allclasses_navbar_top">
|
||
|
|
<li><a href="../../../allclasses-noframe.html">All Classes</a></li>
|
||
|
|
</ul>
|
||
|
|
<div>
|
||
|
|
<script type="text/javascript"><!--
|
||
|
|
allClassesLink = document.getElementById("allclasses_navbar_top");
|
||
|
|
if(window==top) {
|
||
|
|
allClassesLink.style.display = "block";
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
allClassesLink.style.display = "none";
|
||
|
|
}
|
||
|
|
//-->
|
||
|
|
</script>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<ul class="subNavList">
|
||
|
|
<li>Summary: </li>
|
||
|
|
<li>Nested | </li>
|
||
|
|
<li><a href="#enum.constant.summary">Enum Constants</a> | </li>
|
||
|
|
<li>Field | </li>
|
||
|
|
<li><a href="#method.summary">Method</a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="subNavList">
|
||
|
|
<li>Detail: </li>
|
||
|
|
<li><a href="#enum.constant.detail">Enum Constants</a> | </li>
|
||
|
|
<li>Field | </li>
|
||
|
|
<li><a href="#method.detail">Method</a></li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<a name="skip.navbar.top">
|
||
|
|
<!-- -->
|
||
|
|
</a></div>
|
||
|
|
<!-- ========= END OF TOP NAVBAR ========= -->
|
||
|
|
<!-- ======== START OF CLASS DATA ======== -->
|
||
|
|
<div class="header">
|
||
|
|
<div class="subTitle">com.sleepycat.je</div>
|
||
|
|
<h2 title="Enum CacheMode" class="title">Enum CacheMode</h2>
|
||
|
|
</div>
|
||
|
|
<div class="contentContainer">
|
||
|
|
<ul class="inheritance">
|
||
|
|
<li>java.lang.Object</li>
|
||
|
|
<li>
|
||
|
|
<ul class="inheritance">
|
||
|
|
<li>java.lang.Enum<<a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a>></li>
|
||
|
|
<li>
|
||
|
|
<ul class="inheritance">
|
||
|
|
<li>com.sleepycat.je.CacheMode</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<div class="description">
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<dl>
|
||
|
|
<dt>All Implemented Interfaces:</dt>
|
||
|
|
<dd>java.io.Serializable, java.lang.Comparable<<a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a>></dd>
|
||
|
|
</dl>
|
||
|
|
<hr>
|
||
|
|
<br>
|
||
|
|
<pre>public enum <span class="typeNameLabel">CacheMode</span>
|
||
|
|
extends java.lang.Enum<<a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a>></pre>
|
||
|
|
<div class="block">Modes that can be specified for control over caching of records in the JE
|
||
|
|
in-memory cache. When a record is stored or retrieved, the cache mode
|
||
|
|
determines how long the record is subsequently retained in the JE in-memory
|
||
|
|
cache, relative to other records in the cache.
|
||
|
|
|
||
|
|
<p>When the cache overflows, JE must evict some records from the cache. By
|
||
|
|
default, JE uses a Least Recently Used (LRU) algorithm for determining which
|
||
|
|
records to evict. With the LRU algorithm, JE makes a best effort to evict
|
||
|
|
the "coldest" (least recently used or accessed) records and to retain the
|
||
|
|
"hottest" records in the cache for as long as possible.</p>
|
||
|
|
|
||
|
|
<p>When an <a href="../../../com/sleepycat/je/EnvironmentMutableConfig.html#setOffHeapCacheSize-long-"><code>off-heap
|
||
|
|
cache</code></a> is configured, records evicted from the main cache are placed in
|
||
|
|
the off-heap cache, and a separate LRU is used to determine when to evict
|
||
|
|
a record from the off-heap cache.</p>
|
||
|
|
|
||
|
|
<p>JE uses an approximate LRU approach with some exceptions and special
|
||
|
|
cases.</p>
|
||
|
|
<ul>
|
||
|
|
<li>
|
||
|
|
Individual records (LNs or Leaf Nodes) do not appear on the LRU
|
||
|
|
list, i.e., their "hotness" is not explicitly tracked. Instead,
|
||
|
|
their containing Btree node (BIN or bottom internal node) appears on
|
||
|
|
the LRU list. Each BIN contains roughly 100 LNs
|
||
|
|
(see <a href="../../../com/sleepycat/je/EnvironmentConfig.html#NODE_MAX_ENTRIES"><code>EnvironmentConfig.NODE_MAX_ENTRIES</code></a>).
|
||
|
|
When an LN is accessed, its BIN is moved to the hot end of the LRU
|
||
|
|
list, implying that all other LNs in the same BIN also are treated
|
||
|
|
as if they are hot. The same applies if the BIN is moved to the cold
|
||
|
|
end of the LRU list. The above statement applies to the off-heap
|
||
|
|
cache also, when one is configured.
|
||
|
|
</li>
|
||
|
|
<li>
|
||
|
|
When a BIN contains LNs and the BIN reaches the cold end of the LRU
|
||
|
|
list, memory can be reclaimed by evicting the LNs, and eviction of
|
||
|
|
the BIN is deferred. The empty BIN is moved to the hot end of the
|
||
|
|
LRU list. When an off-heap cache is configured, the eviction of LNs
|
||
|
|
in this manner occurs independently in both caches.
|
||
|
|
</li>
|
||
|
|
<li>
|
||
|
|
When a BIN contains no LNs, it may be evicted entirely. When the
|
||
|
|
BINs parent node becomes empty, it may also be evicted, and so on.
|
||
|
|
The BINs and INs are evicted on the basis of an LRU, but with two
|
||
|
|
exceptions:
|
||
|
|
<p>
|
||
|
|
1) Dirty BINs and INs are evicted only after eviction of all
|
||
|
|
non-dirty BINs and INs. This is important to reduce logging and
|
||
|
|
associated cleaning costs. When an off-heap cache is configured,
|
||
|
|
BINs and INs are evicted from the main cache without regard to
|
||
|
|
whether they are dirty. Dirty BINs and INs are evicted last, as
|
||
|
|
just described, only from the off-heap cache.
|
||
|
|
<p>
|
||
|
|
2) A BIN may be mutated to a BIN-delta to reclaim memory, rather
|
||
|
|
then being evicted entirely. A BIN-delta contains only the dirty
|
||
|
|
entries (for LNs recently logged). A BIN-delta is used when its
|
||
|
|
size relative to the full BIN will be small enough so that it will
|
||
|
|
be more efficient, both on disk and in memory, to store the delta
|
||
|
|
rather than the full BIN.
|
||
|
|
(see <a href="../../../com/sleepycat/je/EnvironmentConfig.html#TREE_BIN_DELTA"><code>EnvironmentConfig.TREE_BIN_DELTA</code></a>).
|
||
|
|
The advantage of keeping a BIN-delta in cache is that some
|
||
|
|
operations, particularly record insertions, can be performed using
|
||
|
|
the delta without having the complete BIN in cache. When a BIN is
|
||
|
|
mutated to a BIN-delta to reclaim memory, it is placed at the hot
|
||
|
|
end of the LRU list. When an off-heap cache is configured, BINs are
|
||
|
|
not mutated to BIN-deltas in the main cache, but rather this is done
|
||
|
|
only in the off-heap cache.
|
||
|
|
</li>
|
||
|
|
<li>
|
||
|
|
To reduce contention among threads on the LRU list, multiple LRU
|
||
|
|
lists may be configured. See
|
||
|
|
<a href="../../../com/sleepycat/je/EnvironmentConfig.html#EVICTOR_N_LRU_LISTS"><code>EnvironmentConfig.EVICTOR_N_LRU_LISTS</code></a>.
|
||
|
|
As described in the javadoc for this parameter, there is a trade-off
|
||
|
|
between thread contention and the accuracy of the LRU. This
|
||
|
|
parameter determines the number of main cache LRU lists as well as
|
||
|
|
the number of off-heap cache LRU lists, when an off-heap cache is
|
||
|
|
configured.
|
||
|
|
</li>
|
||
|
|
<li>
|
||
|
|
A non-default cache mode may be explicitly specified to override
|
||
|
|
the LRU behavior. See the CacheMode enumeration values for details.
|
||
|
|
the normal LRU behavior described above. See the CacheMode
|
||
|
|
enumeration values for details. The behavior of each CacheMode
|
||
|
|
when an off-heap cache is configured is also described.
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<p>When no cache mode is explicitly specified, the default cache mode is
|
||
|
|
<a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a>. The default mode causes the normal LRU algorithm to be
|
||
|
|
used.</p>
|
||
|
|
|
||
|
|
<p>An explicit cache mode may be specified as an <a href="../../../com/sleepycat/je/EnvironmentMutableConfig.html#setCacheMode-com.sleepycat.je.CacheMode-"><code>Environment property</code></a>, a <a href="../../../com/sleepycat/je/DatabaseConfig.html#setCacheMode-com.sleepycat.je.CacheMode-"><code>Database property</code></a>, a <a href="../../../com/sleepycat/je/Cursor.html#setCacheMode-com.sleepycat.je.CacheMode-"><code>Cursor property</code></a>, or on a per-operation basis using
|
||
|
|
<a href="../../../com/sleepycat/je/ReadOptions.html#setCacheMode-com.sleepycat.je.CacheMode-"><code>ReadOptions.setCacheMode(CacheMode)</code></a> or <a href="../../../com/sleepycat/je/WriteOptions.html#setCacheMode-com.sleepycat.je.CacheMode-"><code>WriteOptions.setCacheMode(CacheMode)</code></a>. If none are specified, <a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a> is used. If more than one non-null property is specified, the
|
||
|
|
Cursor property overrides the Database and Environment properties, and the
|
||
|
|
Database property overrides the Environment property.</p>
|
||
|
|
|
||
|
|
<p>When all records in a given Database, or all Databases, should be treated
|
||
|
|
the same with respect to caching, using the Database and/or Environment
|
||
|
|
cache mode properties is sufficient. For applications that need finer
|
||
|
|
grained control, the Cursor cache mode property can be used to provide a
|
||
|
|
specific cache mode for individual records or operations. The Cursor cache
|
||
|
|
mode property can be changed at any time, and the cache mode specified will
|
||
|
|
apply to subsequent operations performed with that Cursor.</p>
|
||
|
|
|
||
|
|
<p>In a Replicated Environment where a non-default cache mode is desired,
|
||
|
|
the cache mode can be configured on the Master node as described above.
|
||
|
|
However, it is important to configure the cache mode on the Replica nodes
|
||
|
|
using an Environment property. That way, the cache mode will apply to
|
||
|
|
<em>write</em> operations that are replayed on the Replica for all
|
||
|
|
Databases, even if the Databases are not open by the application on the
|
||
|
|
Replica. Since all nodes may be Replicas at some point in their life cycle,
|
||
|
|
it is recommended to configure the desired cache mode as an Environment
|
||
|
|
property on all nodes in a Replicated Environment.</p>
|
||
|
|
|
||
|
|
<p>On a Replica, per-Database control over the cache mode for <em>write</em>
|
||
|
|
operations is possible by opening the Database on the Replica and
|
||
|
|
configuring the cache mode. Per-Cursor control (meaning per-record or
|
||
|
|
per-operation) control of the cache mode is not possible on a Replica for
|
||
|
|
<em>write</em> operations. For <em>read</em> operations, both per-Database
|
||
|
|
and per-Cursor control is possible on the Replica, as described above.</p>
|
||
|
|
<p>
|
||
|
|
The cache related stats in <a href="../../../com/sleepycat/je/EnvironmentStats.html" title="class in com.sleepycat.je"><code>EnvironmentStats</code></a> can provide some measure
|
||
|
|
of the effectiveness of the cache mode choice.</div>
|
||
|
|
<dl>
|
||
|
|
<dt><span class="seeLabel">See Also:</span></dt>
|
||
|
|
<dd><a href="EnvironmentStats.html#cacheSizing">Cache Statistics:
|
||
|
|
Sizing</a></dd>
|
||
|
|
</dl>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<div class="summary">
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<!-- =========== ENUM CONSTANT SUMMARY =========== -->
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="enum.constant.summary">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Enum Constant Summary</h3>
|
||
|
|
<table class="memberSummary" border="0" cellpadding="3" cellspacing="0" summary="Enum Constant Summary table, listing enum constants, and an explanation">
|
||
|
|
<caption><span>Enum Constants</span><span class="tabEnd"> </span></caption>
|
||
|
|
<tr>
|
||
|
|
<th class="colOne" scope="col">Enum Constant and Description</th>
|
||
|
|
</tr>
|
||
|
|
<tr class="altColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT">DEFAULT</a></span></code>
|
||
|
|
<div class="block">The record's hotness is changed to "most recently used" by the
|
||
|
|
operation.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr class="rowColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#EVICT_BIN">EVICT_BIN</a></span></code>
|
||
|
|
<div class="block">The record's BIN (and its LNs) are evicted after the operation.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr class="altColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#EVICT_LN">EVICT_LN</a></span></code>
|
||
|
|
<div class="block">The record's LN is evicted after the operation, and the containing
|
||
|
|
BIN is moved to the hot end of the LRU list.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr class="rowColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#KEEP_HOT">KEEP_HOT</a></span></code>
|
||
|
|
<div class="block"><span class="deprecatedLabel">Deprecated.</span>
|
||
|
|
<div class="block"><span class="deprecationComment">please use <a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a> instead. As of JE 4.0, this mode
|
||
|
|
functions exactly as if <a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a> were specified.</span></div>
|
||
|
|
</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr class="altColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#MAKE_COLD">MAKE_COLD</a></span></code>
|
||
|
|
<div class="block"><span class="deprecatedLabel">Deprecated.</span>
|
||
|
|
<div class="block"><span class="deprecationComment">please use <a href="../../../com/sleepycat/je/CacheMode.html#UNCHANGED"><code>UNCHANGED</code></a> instead. As of JE 4.0, this
|
||
|
|
mode functions exactly as if <a href="../../../com/sleepycat/je/CacheMode.html#UNCHANGED"><code>UNCHANGED</code></a> were specified.</span></div>
|
||
|
|
</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr class="rowColor">
|
||
|
|
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#UNCHANGED">UNCHANGED</a></span></code>
|
||
|
|
<div class="block">The record's hotness or coldness is unchanged by the operation where
|
||
|
|
this cache mode is specified.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<!-- ========== METHOD SUMMARY =========== -->
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="method.summary">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Method Summary</h3>
|
||
|
|
<table class="memberSummary" border="0" cellpadding="3" cellspacing="0" summary="Method Summary table, listing methods, and an explanation">
|
||
|
|
<caption><span id="t0" class="activeTableTab"><span>All Methods</span><span class="tabEnd"> </span></span><span id="t1" class="tableTab"><span><a href="javascript:show(1);">Static Methods</a></span><span class="tabEnd"> </span></span><span id="t4" class="tableTab"><span><a href="javascript:show(8);">Concrete Methods</a></span><span class="tabEnd"> </span></span></caption>
|
||
|
|
<tr>
|
||
|
|
<th class="colFirst" scope="col">Modifier and Type</th>
|
||
|
|
<th class="colLast" scope="col">Method and Description</th>
|
||
|
|
</tr>
|
||
|
|
<tr id="i0" class="altColor">
|
||
|
|
<td class="colFirst"><code>static <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a></code></td>
|
||
|
|
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#valueOf-java.lang.String-">valueOf</a></span>(java.lang.String name)</code>
|
||
|
|
<div class="block">Returns the enum constant of this type with the specified name.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr id="i1" class="rowColor">
|
||
|
|
<td class="colFirst"><code>static <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a>[]</code></td>
|
||
|
|
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/je/CacheMode.html#values--">values</a></span>()</code>
|
||
|
|
<div class="block">Returns an array containing the constants of this enum type, in
|
||
|
|
the order they are declared.</div>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="methods.inherited.from.class.java.lang.Enum">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Methods inherited from class java.lang.Enum</h3>
|
||
|
|
<code>clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf</code></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="methods.inherited.from.class.java.lang.Object">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Methods inherited from class java.lang.Object</h3>
|
||
|
|
<code>getClass, notify, notifyAll, wait, wait, wait</code></li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<div class="details">
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<!-- ============ ENUM CONSTANT DETAIL =========== -->
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="enum.constant.detail">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Enum Constant Detail</h3>
|
||
|
|
<a name="DEFAULT">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>DEFAULT</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> DEFAULT</pre>
|
||
|
|
<div class="block">The record's hotness is changed to "most recently used" by the
|
||
|
|
operation.
|
||
|
|
|
||
|
|
<p>This cache mode is used when the application does not need explicit
|
||
|
|
control over the cache and a standard LRU approach is sufficient.</p>
|
||
|
|
|
||
|
|
<p>Note that <code>null</code> may be specified to use the <code>DEFAULT</code>
|
||
|
|
mode.</p>
|
||
|
|
|
||
|
|
<p>Specifically:
|
||
|
|
<ul>
|
||
|
|
<li>The BIN containing the record's LN will remain in the main
|
||
|
|
cache, and it is moved to the hot end of its LRU list.</li>
|
||
|
|
|
||
|
|
<li>When an off-heap cache is configured, the record's LN and BIN
|
||
|
|
will be loaded into the main cache only. They will be removed from
|
||
|
|
the off-heap cache, if they were present there. However, if other
|
||
|
|
LNs belonging to this BIN were present in the off-heap cache, they
|
||
|
|
will remain there.</li>
|
||
|
|
<ul></div>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="KEEP_HOT">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>KEEP_HOT</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> KEEP_HOT</pre>
|
||
|
|
<div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">please use <a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a> instead. As of JE 4.0, this mode
|
||
|
|
functions exactly as if <a href="../../../com/sleepycat/je/CacheMode.html#DEFAULT"><code>DEFAULT</code></a> were specified.</span></div>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="UNCHANGED">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>UNCHANGED</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> UNCHANGED</pre>
|
||
|
|
<div class="block">The record's hotness or coldness is unchanged by the operation where
|
||
|
|
this cache mode is specified.
|
||
|
|
|
||
|
|
<p>This cache mode is normally used when the application prefers that
|
||
|
|
the operation should not perturb the cache, for example, when scanning
|
||
|
|
over all records in a database.</p>
|
||
|
|
|
||
|
|
<p>Specifically:
|
||
|
|
<ul>
|
||
|
|
<li>A record's LN and BIN must be loaded into the main cache in
|
||
|
|
order to perform the operation. However, they may be removed from
|
||
|
|
the main cache after the operation, to avoid a net change to the
|
||
|
|
cache, according to the rules below.</li>
|
||
|
|
|
||
|
|
<li>If the record's LN was not present in the main cache prior to
|
||
|
|
the operation, then the LN will be evicted from the main cache
|
||
|
|
after the operation. The LN will not be added to, or removed from,
|
||
|
|
the off-heap cache.</li>
|
||
|
|
|
||
|
|
<li>When the LN is to be evicted from the main cache (according to
|
||
|
|
the above rules) and the operation is not performed via a cursor,
|
||
|
|
the LN is evicted when the operation is complete. When a cursor is
|
||
|
|
used, the LN is evicted when the cursor is moved to a different
|
||
|
|
record or closed.</li>
|
||
|
|
|
||
|
|
<li>If the record's BIN was not present in the main cache prior to
|
||
|
|
the operation, the action taken depends on whether the BIN is dirty
|
||
|
|
and whether an off-heap cache is configured.
|
||
|
|
<ul>
|
||
|
|
<li>When the BIN is not dirty, the BIN (and LN) will be evicted
|
||
|
|
from the main cache after the operation. The BIN (and LN) will
|
||
|
|
not be added to, or removed from, the off-heap cache.</li>
|
||
|
|
|
||
|
|
<li>When the BIN is dirty and an off-heap cache is
|
||
|
|
<em>not</em> configured, the BIN will not be evicted from the
|
||
|
|
main cache and will be moved to the hot end of its main cache
|
||
|
|
LRU list. This is done to reduce logging.</li>
|
||
|
|
|
||
|
|
<li>When the BIN is dirty and an off-heap cache <em>is</em>
|
||
|
|
configured, we evict the BIN from the main cache even when it
|
||
|
|
is dirty because the BIN (and LN) will be stored in the off-heap
|
||
|
|
cache and the BIN will not be logged. The BIN will be placed at
|
||
|
|
the hot end of its off-heap LRU list.</li>
|
||
|
|
|
||
|
|
<li>Note that when this operation loaded the BIN and the BIN
|
||
|
|
becomes dirty, it is normally because this operation is a write
|
||
|
|
operation. However, other concurrent threads can also dirty the
|
||
|
|
BIN.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<li>When the BIN is to be evicted from the main cache (according
|
||
|
|
to the above rules) and the operation is not performed via a
|
||
|
|
cursor, the BIN is evicted when the operation is complete. When a
|
||
|
|
cursor is used, the BIN is evicted only when the cursor moves to a
|
||
|
|
different BIN or is closed. Because of the way BINs are evicted,
|
||
|
|
when multiple operations are performed using a single cursor and
|
||
|
|
not perturbing the cache is desired, it is important to use this
|
||
|
|
cache mode for all of the operations.</li>
|
||
|
|
|
||
|
|
<li>When the BIN was present in the main cache prior to the
|
||
|
|
operation, its position in the LRU list will not be changed. Its
|
||
|
|
position in the off-heap LRU list, if it is present in the off-heap
|
||
|
|
cache, will also not be changed.</li>
|
||
|
|
</ul></div>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="MAKE_COLD">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>MAKE_COLD</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> MAKE_COLD</pre>
|
||
|
|
<div class="block"><span class="deprecatedLabel">Deprecated.</span> <span class="deprecationComment">please use <a href="../../../com/sleepycat/je/CacheMode.html#UNCHANGED"><code>UNCHANGED</code></a> instead. As of JE 4.0, this
|
||
|
|
mode functions exactly as if <a href="../../../com/sleepycat/je/CacheMode.html#UNCHANGED"><code>UNCHANGED</code></a> were specified.</span></div>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="EVICT_LN">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>EVICT_LN</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> EVICT_LN</pre>
|
||
|
|
<div class="block">The record's LN is evicted after the operation, and the containing
|
||
|
|
BIN is moved to the hot end of the LRU list.
|
||
|
|
|
||
|
|
<p>This cache mode is normally used when not all LNs will fit into the
|
||
|
|
main cache, and the application prefers to read the LN from the log file
|
||
|
|
or load it from the off-heap cache when the record is accessed again,
|
||
|
|
rather than have it take up space in the main cache and potentially
|
||
|
|
cause expensive Java GC. By using this mode, the file system cache or
|
||
|
|
off-heap cache can be relied on for holding LNs, which complements the
|
||
|
|
use of the JE cache to hold BINs and INs.</p>
|
||
|
|
|
||
|
|
<p>Note that using this mode for all operations will prevent the cache
|
||
|
|
from filling, if all internal nodes fit in cache.</p>
|
||
|
|
|
||
|
|
<p>Specifically:
|
||
|
|
<ul>
|
||
|
|
<li>The record's LN will be evicted from the main cache after the
|
||
|
|
operation. The LN will be added to the off-heap cache, if it is not
|
||
|
|
already present and an off-heap cache is configured.</li>
|
||
|
|
|
||
|
|
<li>When the operation is not performed via a cursor, the LN is
|
||
|
|
evicted when the operation is complete. When a cursor is used, the
|
||
|
|
LN is evicted when the cursor is moved to a different record or
|
||
|
|
closed.</li>
|
||
|
|
</ul></div>
|
||
|
|
<dl>
|
||
|
|
<dt><span class="simpleTagLabel">Since:</span></dt>
|
||
|
|
<dd>3.3.98</dd>
|
||
|
|
</dl>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="EVICT_BIN">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockListLast">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>EVICT_BIN</h4>
|
||
|
|
<pre>public static final <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> EVICT_BIN</pre>
|
||
|
|
<div class="block">The record's BIN (and its LNs) are evicted after the operation.
|
||
|
|
|
||
|
|
<p>This cache mode is normally used when not all BINs will fit into the
|
||
|
|
main cache, and the application prefers to read the LN and BIN from the
|
||
|
|
log file or load it from the off-heap cache when the record is accessed
|
||
|
|
again, rather than have them take up space in the JE cache and
|
||
|
|
potentially cause expensive Java GC.</p>
|
||
|
|
|
||
|
|
<p>Because this mode evicts all LNs in the BIN, even if they are "hot"
|
||
|
|
from the perspective of a different accessor, this mode should be used
|
||
|
|
with caution. One valid use case is where all accessors use this mode;
|
||
|
|
in this case the cache mode might be set on a per-Database or
|
||
|
|
per-Environment basis.</p>
|
||
|
|
|
||
|
|
<p>Note that using this mode for all operations will prevent the cache
|
||
|
|
from filling, if all upper internal nodes fit in cache.</p>
|
||
|
|
|
||
|
|
<p>Specifically:
|
||
|
|
<ul>
|
||
|
|
<li>The record's LN will be evicted from the main cache after the
|
||
|
|
operation. The LN will be added to the off-heap cache, if it is not
|
||
|
|
already present and an off-heap cache is configured.</li>
|
||
|
|
|
||
|
|
<li>When the operation is not performed via a cursor, the LN is
|
||
|
|
evicted when the operation is complete. When a cursor is used, the
|
||
|
|
LN is evicted when the cursor is moved to a different record or
|
||
|
|
closed.</li>
|
||
|
|
|
||
|
|
<li>Whether the BIN is evicted depends on whether the BIN is dirty
|
||
|
|
and whether an off-heap cache is configured.
|
||
|
|
<ul>
|
||
|
|
<li>When the BIN is not dirty, the BIN (and LN) will be evicted
|
||
|
|
from the main cache after the operation. The BIN (and LN) will
|
||
|
|
be added to the off-heap cache, if they are not already present
|
||
|
|
and an off-heap cache is configured. The BIN will be placed at
|
||
|
|
the hot end of its off-heap LRU list.</li>
|
||
|
|
|
||
|
|
<li>When the BIN is dirty and an off-heap cache is
|
||
|
|
<em>not</em> configured, the BIN will not be evicted from the
|
||
|
|
main cache and will be moved to the hot end of its main cache
|
||
|
|
LRU list. This is done to reduce logging.</li>
|
||
|
|
|
||
|
|
<li>When the BIN is dirty and an off-heap cache <em>is</em>
|
||
|
|
configured, we evict the BIN from the main cache even when it
|
||
|
|
is dirty because the BIN (and LN) will be stored in the off-heap
|
||
|
|
cache and the BIN will not be logged. The BIN will be placed at
|
||
|
|
the hot end of its off-heap LRU list.</li>
|
||
|
|
|
||
|
|
<li>Note that BIN may have been dirtied by this operation, if
|
||
|
|
it is a write operation, or by earlier write operations.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<li>When the BIN is to be evicted from the main cache (according
|
||
|
|
to the above rules) and the operation is not performed via a
|
||
|
|
cursor, the BIN is evicted when the operation is complete. When a
|
||
|
|
cursor is used, the BIN is evicted only when the cursor moves to a
|
||
|
|
different BIN or is closed. Because of the way BINs are evicted,
|
||
|
|
when multiple operations are performed using a single cursor and
|
||
|
|
not perturbing the cache is desired, it is important to use this
|
||
|
|
cache mode for all of the operations.</li>
|
||
|
|
</ul></div>
|
||
|
|
<dl>
|
||
|
|
<dt><span class="simpleTagLabel">Since:</span></dt>
|
||
|
|
<dd>4.0.97</dd>
|
||
|
|
</dl>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<!-- ============ METHOD DETAIL ========== -->
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList"><a name="method.detail">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<h3>Method Detail</h3>
|
||
|
|
<a name="values--">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockList">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>values</h4>
|
||
|
|
<pre>public static <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a>[] values()</pre>
|
||
|
|
<div class="block">Returns an array containing the constants of this enum type, in
|
||
|
|
the order they are declared. This method may be used to iterate
|
||
|
|
over the constants as follows:
|
||
|
|
<pre>
|
||
|
|
for (CacheMode c : CacheMode.values())
|
||
|
|
System.out.println(c);
|
||
|
|
</pre></div>
|
||
|
|
<dl>
|
||
|
|
<dt><span class="returnLabel">Returns:</span></dt>
|
||
|
|
<dd>an array containing the constants of this enum type, in the order they are declared</dd>
|
||
|
|
</dl>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<a name="valueOf-java.lang.String-">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="blockListLast">
|
||
|
|
<li class="blockList">
|
||
|
|
<h4>valueOf</h4>
|
||
|
|
<pre>public static <a href="../../../com/sleepycat/je/CacheMode.html" title="enum in com.sleepycat.je">CacheMode</a> valueOf(java.lang.String name)</pre>
|
||
|
|
<div class="block">Returns the enum constant of this type with the specified name.
|
||
|
|
The string must match <i>exactly</i> an identifier used to declare an
|
||
|
|
enum constant in this type. (Extraneous whitespace characters are
|
||
|
|
not permitted.)</div>
|
||
|
|
<dl>
|
||
|
|
<dt><span class="paramLabel">Parameters:</span></dt>
|
||
|
|
<dd><code>name</code> - the name of the enum constant to be returned.</dd>
|
||
|
|
<dt><span class="returnLabel">Returns:</span></dt>
|
||
|
|
<dd>the enum constant with the specified name</dd>
|
||
|
|
<dt><span class="throwsLabel">Throws:</span></dt>
|
||
|
|
<dd><code>java.lang.IllegalArgumentException</code> - if this enum type has no constant with the specified name</dd>
|
||
|
|
<dd><code>java.lang.NullPointerException</code> - if the argument is null</dd>
|
||
|
|
</dl>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<!-- ========= END OF CLASS DATA ========= -->
|
||
|
|
<!-- ======= START OF BOTTOM NAVBAR ====== -->
|
||
|
|
<div class="bottomNav"><a name="navbar.bottom">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<div class="skipNav"><a href="#skip.navbar.bottom" title="Skip navigation links">Skip navigation links</a></div>
|
||
|
|
<a name="navbar.bottom.firstrow">
|
||
|
|
<!-- -->
|
||
|
|
</a>
|
||
|
|
<ul class="navList" title="Navigation">
|
||
|
|
<li><a href="../../../overview-summary.html">Overview</a></li>
|
||
|
|
<li><a href="package-summary.html">Package</a></li>
|
||
|
|
<li class="navBarCell1Rev">Class</li>
|
||
|
|
<li><a href="class-use/CacheMode.html">Use</a></li>
|
||
|
|
<li><a href="package-tree.html">Tree</a></li>
|
||
|
|
<li><a href="../../../deprecated-list.html">Deprecated</a></li>
|
||
|
|
<li><a href="../../../index-all.html">Index</a></li>
|
||
|
|
<li><a href="../../../help-doc.html">Help</a></li>
|
||
|
|
</ul>
|
||
|
|
<div class="aboutLanguage"><b>Berkeley DB Java Edition</b><br><font size=\"-1\"> version 7.5.11</font>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="subNav">
|
||
|
|
<ul class="navList">
|
||
|
|
<li><a href="../../../com/sleepycat/je/BtreeStats.html" title="class in com.sleepycat.je"><span class="typeNameLink">Prev Class</span></a></li>
|
||
|
|
<li><a href="../../../com/sleepycat/je/CheckpointConfig.html" title="class in com.sleepycat.je"><span class="typeNameLink">Next Class</span></a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="navList">
|
||
|
|
<li><a href="../../../index.html?com/sleepycat/je/CacheMode.html" target="_top">Frames</a></li>
|
||
|
|
<li><a href="CacheMode.html" target="_top">No Frames</a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="navList" id="allclasses_navbar_bottom">
|
||
|
|
<li><a href="../../../allclasses-noframe.html">All Classes</a></li>
|
||
|
|
</ul>
|
||
|
|
<div>
|
||
|
|
<script type="text/javascript"><!--
|
||
|
|
allClassesLink = document.getElementById("allclasses_navbar_bottom");
|
||
|
|
if(window==top) {
|
||
|
|
allClassesLink.style.display = "block";
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
allClassesLink.style.display = "none";
|
||
|
|
}
|
||
|
|
//-->
|
||
|
|
</script>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<ul class="subNavList">
|
||
|
|
<li>Summary: </li>
|
||
|
|
<li>Nested | </li>
|
||
|
|
<li><a href="#enum.constant.summary">Enum Constants</a> | </li>
|
||
|
|
<li>Field | </li>
|
||
|
|
<li><a href="#method.summary">Method</a></li>
|
||
|
|
</ul>
|
||
|
|
<ul class="subNavList">
|
||
|
|
<li>Detail: </li>
|
||
|
|
<li><a href="#enum.constant.detail">Enum Constants</a> | </li>
|
||
|
|
<li>Field | </li>
|
||
|
|
<li><a href="#method.detail">Method</a></li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<a name="skip.navbar.bottom">
|
||
|
|
<!-- -->
|
||
|
|
</a></div>
|
||
|
|
<!-- ======== END OF BOTTOM NAVBAR ======= -->
|
||
|
|
<p class="legalCopy"><small><font size=1>Copyright (c) 2002, 2017 Oracle and/or its affiliates. All rights reserved.</font> </small></p>
|
||
|
|
</body>
|
||
|
|
</html>
|