From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 22 Mar 2018 17:23:48 +0000 (-0400)
Subject: Fix tuple counting in SP-GiST index build.
X-Git-Tag: REL9_4_18~47
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7f6f8ccd976da21c0117bddfee8bd86226bd2559;p=postgresql

Fix tuple counting in SP-GiST index build.

Count the number of tuples in the index honestly, instead of assuming
that it's the same as the number of tuples in the heap.  (It might be
different if the index is partial.)

Back-patch to all supported versions.

Tomas Vondra

Discussion: https://postgr.es/m/3b3d8eac-c709-0d25-088e-b98339a1b28a@2ndquadrant.com
---

diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index cf3d11c34c..edb41c1fc0 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -30,6 +30,7 @@
 typedef struct
 {
 	SpGistState spgstate;		/* SPGiST's working state */
+	int64		indtuples;		/* total number of tuples indexed */
 	MemoryContext tmpCtx;		/* per-tuple temporary context */
 } SpGistBuildState;
 
@@ -57,6 +58,9 @@ spgistBuildCallback(Relation index, HeapTuple htup, Datum *values,
 		MemoryContextReset(buildstate->tmpCtx);
 	}
 
+	/* Update total tuple count */
+	buildstate->indtuples += 1;
+
 	MemoryContextSwitchTo(oldCtx);
 	MemoryContextReset(buildstate->tmpCtx);
 }
@@ -130,6 +134,7 @@ spgbuild(PG_FUNCTION_ARGS)
 	 */
 	initSpGistState(&buildstate.spgstate, index);
 	buildstate.spgstate.isBuild = true;
+	buildstate.indtuples = 0;
 
 	buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
 										   "SP-GiST build temporary context",
@@ -145,7 +150,8 @@ spgbuild(PG_FUNCTION_ARGS)
 	SpGistUpdateMetaPage(index);
 
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
-	result->heap_tuples = result->index_tuples = reltuples;
+	result->heap_tuples = reltuples;
+	result->index_tuples = buildstate.indtuples;
 
 	PG_RETURN_POINTER(result);
 }