Make ginbuild's funcCtx be independent of its tmpCtx.

tglsfdc · tglsfdc · commit 1601830ec20d · 2015-03-29T14:02:58.000-04:00
Previously the funcCtx was a child of the tmpCtx, but that was broken by commit eaa5808, which made MemoryContextReset() delete, not reset, child contexts. The behavior of having a tmpCtx reset also clear the other context seems rather dubious anyway, so let's just disentangle them. Per report from Erik Rijkers. In passing, fix badly-inaccurate comments about these contexts.
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
@@ -370,16 +370,20 @@ ginbuild(PG_FUNCTION_ARGS)
 	buildstate.buildStats.nEntryPages++;
 
 	/*
-	 * create a temporary memory context that is reset once for each tuple
-	 * inserted into the index
+	 * create a temporary memory context that is used to hold data not yet
+	 * dumped out to the index
 	 */
 	buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
 											  "Gin build temporary context",
 											  ALLOCSET_DEFAULT_MINSIZE,
 											  ALLOCSET_DEFAULT_INITSIZE,
 											  ALLOCSET_DEFAULT_MAXSIZE);
 
-	buildstate.funcCtx = AllocSetContextCreate(buildstate.tmpCtx,
+	/*
+	 * create a temporary memory context that is used for calling
+	 * ginExtractEntries(), and can be reset after each tuple
+	 */
+	buildstate.funcCtx = AllocSetContextCreate(CurrentMemoryContext,
 					 "Gin build temporary context for user-defined function",
 											   ALLOCSET_DEFAULT_MINSIZE,
 											   ALLOCSET_DEFAULT_INITSIZE,
@@ -408,6 +412,7 @@ ginbuild(PG_FUNCTION_ARGS)
 	}
 	MemoryContextSwitchTo(oldCtx);
 
+	MemoryContextDelete(buildstate.funcCtx);
 	MemoryContextDelete(buildstate.tmpCtx);
 
 	/*
