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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. GOVERNMENT USE: If you are acquiring this software on behalf of the U.S. government, the Government shall have only "Restricted Rights" in the software and related documentation as defined in the Federal Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are acquiring the software on behalf of the Department of Defense, the software shall be classified as "Commercial Computer Software" and the Government shall have only "Restricted Rights" as defined in Clause 252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the authors grant the U.S. Government and others acting in its behalf permission to use and distribute the software in accordance with the terms specified in this license. ---*/ /** * @file * * Interface for defining new logical operations. * * @ingroup LLADD_CORE OPERATIONS * @todo The functions in operations.h don't belong in the API, but it defines some constants and typedefs that should be there. * $Id$ */ #ifndef __OPERATIONS_H__ #define __OPERATIONS_H__ #include #include #include #include BEGIN_C_DECLS /* @type Function * function pointer that the operation will run */ typedef int (*Function)(int xid, Page * p, lsn_t lsn, recordid r, const void *d); /* @type Operation * @param sizeofData size of the data that function accepts (as void*) * @param undo index into operations table of undo function (takes same args) * @param run what function to actually run */ /* @type Special cases */ #define SIZEOF_RECORD -1 #define NO_INVERSE -1 typedef struct { /** * ID of operation, also index into operations table */ int id; /** This value is the size of the arguments that this operation takes. If set to SIZEOF_RECORD, then the size of the record that the operation affects will be used instead. */ long sizeofData; /** Does this operation supply an undo operation? --Unneeded; just set undo to the special value NO_INVERSE. */ /* int invertible; */ /** Implementing operations that may span records is subtle. Recovery assumes that page writes (and therefore logical operations) are atomic. This isn't the case for operations that span records. Instead, there are two (and probably other) choices: - Periodically checkpoint, syncing the data store to disk, and writing a checkpoint operation. No writes can be serviced during the sync, and this implies 'no steal'. See: @inproceedings{ woo97accommodating, author = "Seung-Kyoon Woo and Myoung-Ho Kim and Yoon-Joon Lee", title = "Accommodating Logical Logging under Fuzzy Checkpointing in Main Memory Databases", booktitle = "International Database Engineering and Application Symposium", pages = "53-62", year = "1997", url = "citeseer.ist.psu.edu/135200.html" } for a more complex scheme involving a hybrid logical/physical logging system that does not implement steal. The other option: - Get rid of operations that span records entirely by splitting complex logical operations into simpler one. We chose the second option for now. */ int undo; Function run; } Operation; /* These need to be installed, since they are required by applications that use LLADD. */ #include "operations/increment.h" #include "operations/decrement.h" #include "operations/set.h" #include "operations/prepare.h" #include "operations/lladdhash.h" #include "operations/alloc.h" extern Operation operationsTable[]; /* [MAX_OPERATIONS]; memset somewhere */ /** Performs an operation during normal execution. Does not write to the log, and assumes that the operation's results are not already in the buffer manager. */ void doUpdate(const LogEntry * e, Page * p); /** Undo the update under normal operation, and during recovery. Checks to see if the operation's results are reflected in the contents of the buffer manager. If they are, then it performs the undo. Does not write to the log. This function does not generate CLR because this would result in extra CLRs being generated during recovery. @param e The log entry containing the operation to be undone. @param clr_lsn The lsn of the clr that corresponds to this undo operation. */ void undoUpdate(const LogEntry * e, Page * p, lsn_t clr_lsn); /** Redoes an operation during recovery. This is different than doUpdate because it checks to see if the operation needs to be redone before redoing it. (if(e->lsn > e->rid.lsn) { doUpdate(e); } return) Also, this is the only function in operations.h that can take either CLR or UPDATE log entries. The other functions can only handle update entries. Does not write to the log. */ void redoUpdate(const LogEntry * e); END_C_DECLS #endif