From fd267c1ebc363ae6b1bf586794fa5cc9e8cca43c Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 11 Feb 2006 23:31:34 +0000 Subject: Skip ambulkdelete scan if there's nothing to delete and the index is not partial. None of the existing AMs do anything useful except counting tuples when there's nothing to delete, and we can get a tuple count from the heap as long as it's not a partial index. (hash actually can skip anyway because it maintains a tuple count in the index metapage.) GIST is not currently able to exploit this optimization because, due to failure to index NULLs, GIST is always effectively partial. Possibly we should fix that sometime. Simon Riggs w/ some review by Tom Lane. --- src/backend/access/index/indexam.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'src/backend/access/index/indexam.c') diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 6a681192caf..69c9ecb9189 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.89 2006/02/11 17:14:08 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.90 2006/02/11 23:31:33 tgl Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relation OID @@ -685,6 +685,10 @@ index_getmulti(IndexScanDesc scan, * callback routine tells whether a given main-heap tuple is * to be deleted * + * if callback_state is NULL then there are no tuples to be deleted; + * index AM can choose to avoid work in this case, but must still + * follow the protocol of returning statistical info. + * * return value is an optional palloc'd struct of statistics * ---------------- */ -- cgit v1.2.3