From 604ffd280b955100e5fc24649ee4d42a6f3ebf35 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 25 May 2007 17:54:25 +0000 Subject: Create hooks to let a loadable plugin monitor (or even replace) the planner and/or create plans for hypothetical situations; in particular, investigate plans that would be generated using hypothetical indexes. This is a heavily-rewritten version of the hooks proposed by Gurjeet Singh for his Index Advisor project. In this formulation, the index advisor can be entirely a loadable module instead of requiring a significant part to be in the core backend, and plans can be generated for hypothetical indexes without requiring the creation and rolling-back of system catalog entries. The index advisor patch as-submitted is not compatible with these hooks, but it needs significant work anyway due to other 8.2-to-8.3 planner changes. With these hooks in the core backend, development of the advisor can proceed as a pgfoundry project. --- src/backend/executor/nodeBitmapIndexscan.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'src/backend/executor/nodeBitmapIndexscan.c') diff --git a/src/backend/executor/nodeBitmapIndexscan.c b/src/backend/executor/nodeBitmapIndexscan.c index d3fbf348332..6c14b8a4130 100644 --- a/src/backend/executor/nodeBitmapIndexscan.c +++ b/src/backend/executor/nodeBitmapIndexscan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.22 2007/01/05 22:19:28 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.23 2007/05/25 17:54:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -198,10 +198,12 @@ ExecEndBitmapIndexScan(BitmapIndexScanState *node) #endif /* - * close the index relation + * close the index relation (no-op if we didn't open it) */ - index_endscan(indexScanDesc); - index_close(indexRelationDesc, NoLock); + if (indexScanDesc) + index_endscan(indexScanDesc); + if (indexRelationDesc) + index_close(indexRelationDesc, NoLock); } /* ---------------------------------------------------------------- @@ -256,6 +258,14 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags) indexstate->ss.ss_currentRelation = NULL; indexstate->ss.ss_currentScanDesc = NULL; + /* + * If we are just doing EXPLAIN (ie, aren't going to run the plan), + * stop here. This allows an index-advisor plugin to EXPLAIN a plan + * containing references to nonexistent indexes. + */ + if (eflags & EXEC_FLAG_EXPLAIN_ONLY) + return indexstate; + /* * Open the index relation. * -- cgit v1.2.3