Improve GIN index build's tracking of memory usage by using

GetMemoryChunkSpace, not just the palloc request size.  This brings the
allocatedMemory counter close enough to reality (as measured by
MemoryContextStats printouts) that I think we can get rid of the arbitrary
factor-of-2 adjustment that was put into the code initially.  Given the
sensitivity of GIN build to work memory size, not using as much of work
memory as we're allowed to seems a pretty bad idea.

1 files changed, 10 insertions, 7 deletions

diff --git a/src/backend/access/gin/ginbulk.c b/src/backend/access/gin/ginbulk.c
index d0ac0b62121..09dd0094907 100644
--- a/src/backend/access/gin/ginbulk.c
+++ b/src/backend/access/gin/ginbulk.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.9 2007/02/01 04:16:08 neilc Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.10 2007/11/16 21:55:59 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -16,6 +16,7 @@
 
 #include "access/gin.h"
 #include "utils/datum.h"
+#include "utils/memutils.h"
 
 
 #define DEF_NENTRY	2048
@@ -38,7 +39,7 @@ EAAllocate(BuildAccumulator *accum)
 	if (accum->entryallocator == NULL || accum->length >= DEF_NENTRY)
 	{
 		accum->entryallocator = palloc(sizeof(EntryAccumulator) * DEF_NENTRY);
-		accum->allocatedMemory += sizeof(EntryAccumulator) * DEF_NENTRY;
+		accum->allocatedMemory += GetMemoryChunkSpace(accum->entryallocator);
 		accum->length = 0;
 	}
 
@@ -55,10 +56,11 @@ ginInsertData(BuildAccumulator *accum, EntryAccumulator *entry, ItemPointer heap
 {
 	if (entry->number >= entry->length)
 	{
-		accum->allocatedMemory += sizeof(ItemPointerData) * entry->length;
+		accum->allocatedMemory -= GetMemoryChunkSpace(entry->list);
 		entry->length *= 2;
 		entry->list = (ItemPointerData *) repalloc(entry->list,
 									sizeof(ItemPointerData) * entry->length);
+		accum->allocatedMemory += GetMemoryChunkSpace(entry->list);
 	}
 
 	if (entry->shouldSort == FALSE)
@@ -95,10 +97,10 @@ getDatumCopy(BuildAccumulator *accum, Datum value)
 		realSize = datumGetSize(value, false, att[0]->attlen);
 
 		s = (char *) palloc(realSize);
+		accum->allocatedMemory += GetMemoryChunkSpace(s);
+
 		memcpy(s, DatumGetPointer(value), realSize);
 		res = PointerGetDatum(s);
-
-		accum->allocatedMemory += realSize;
 	}
 	return res;
 }
@@ -143,8 +145,8 @@ ginInsertEntry(BuildAccumulator *accum, ItemPointer heapptr, Datum entry)
 		ea->number = 1;
 		ea->shouldSort = FALSE;
 		ea->list = (ItemPointerData *) palloc(sizeof(ItemPointerData) * DEF_NPTR);
+		accum->allocatedMemory += GetMemoryChunkSpace(ea->list);
 		ea->list[0] = *heapptr;
-		accum->allocatedMemory += sizeof(ItemPointerData) * DEF_NPTR;
 
 		if (pea == NULL)
 			accum->entries = ea;
@@ -270,11 +272,11 @@ ginGetEntry(BuildAccumulator *accum, Datum *value, uint32 *n)
 	EntryAccumulator *entry;
 	ItemPointerData *list;
 
-
 	if (accum->stack == NULL)
 	{
 		/* first call */
 		accum->stack = palloc0(sizeof(EntryAccumulator *) * (accum->maxdepth + 1));
+		accum->allocatedMemory += GetMemoryChunkSpace(accum->stack);
 		entry = accum->entries;
 
 		if (entry == NULL)
@@ -295,6 +297,7 @@ ginGetEntry(BuildAccumulator *accum, Datum *value, uint32 *n)
 	}
 	else
 	{
+		accum->allocatedMemory -= GetMemoryChunkSpace(accum->stack[accum->stackpos]->list);
 		pfree(accum->stack[accum->stackpos]->list);
 		accum->stack[accum->stackpos]->list = NULL;
 		entry = walkTree(accum);