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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-09-20 17:56:33 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-09-20 17:56:33 +0000 |
| commit | 282d2a03dd30804b01f8042f640d638c2ee76604 (patch) | |
| tree | 004f08ce31f1bfb03ab55571ad7867babe5b3d7f /src/include/utils/plancache.h | |
| parent | bbf4fdc2538097bb3103806e1419ceef1f289203 (diff) | |
| download | postgresql-282d2a03dd30804b01f8042f640d638c2ee76604.tar.gz postgresql-282d2a03dd30804b01f8042f640d638c2ee76604.zip | |
HOT updates. When we update a tuple without changing any of its indexed
columns, and the new version can be stored on the same heap page, we no longer
generate extra index entries for the new version. Instead, index searches
follow the HOT-chain links to ensure they find the correct tuple version.
In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.
Pavan Deolasee, with help from a bunch of other people.
Diffstat (limited to 'src/include/utils/plancache.h')
| -rw-r--r-- | src/include/utils/plancache.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/include/utils/plancache.h b/src/include/utils/plancache.h index d8152142aac..0a91e886e29 100644 --- a/src/include/utils/plancache.h +++ b/src/include/utils/plancache.h @@ -8,7 +8,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/utils/plancache.h,v 1.7 2007/06/05 20:00:41 wieck Exp $ + * $PostgreSQL: pgsql/src/include/utils/plancache.h,v 1.8 2007/09/20 17:56:32 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -75,6 +75,8 @@ typedef struct CachedPlan List *stmt_list; /* list of statement or Query nodes */ bool fully_planned; /* do we cache planner or rewriter output? */ bool dead; /* if true, do not use */ + TransactionId saved_xmin; /* if valid, replan when TransactionXmin + * changes from this value */ int refcount; /* count of live references to this struct */ int generation; /* counter, starting at 1, for replans */ MemoryContext context; /* context containing this CachedPlan */ |