From 282d2a03dd30804b01f8042f640d638c2ee76604 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 20 Sep 2007 17:56:33 +0000 Subject: 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. --- src/backend/executor/execMain.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'src/backend/executor/execMain.c') diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 7e5873b89df..485f6ddc1ee 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -26,7 +26,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.297 2007/09/07 20:59:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.298 2007/09/20 17:56:31 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1813,8 +1813,10 @@ lreplace:; * * Note: heap_update returns the tid (location) of the new tuple in the * t_self field. + * + * If it's a HOT update, we mustn't insert new index entries. */ - if (resultRelInfo->ri_NumIndices > 0) + if (resultRelInfo->ri_NumIndices > 0 && !HeapTupleIsHeapOnly(tuple)) ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false); /* AFTER ROW UPDATE Triggers */ -- cgit v1.2.3