*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.96.2.3 2007/06/01 15:58:09 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.96.2.4 2009/10/30 20:59:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
int tupsize;
double inner_rel_bytes;
long hash_table_bytes;
+ long max_pointers;
int nbatch;
int nbuckets;
int i;
/*
* Set nbuckets to achieve an average bucket load of NTUP_PER_BUCKET when
* memory is filled. Set nbatch to the smallest power of 2 that appears
- * sufficient.
+ * sufficient. The Min() steps limit the results so that the pointer
+ * arrays we'll try to allocate do not exceed work_mem.
*/
+ max_pointers = (work_mem * 1024L) / sizeof(void *);
+ /* also ensure we avoid integer overflow in nbatch and nbuckets */
+ max_pointers = Min(max_pointers, INT_MAX / 2);
+
if (inner_rel_bytes > hash_table_bytes)
{
/* We'll need multiple batches */
int minbatch;
lbuckets = (hash_table_bytes / tupsize) / NTUP_PER_BUCKET;
- lbuckets = Min(lbuckets, INT_MAX);
+ lbuckets = Min(lbuckets, max_pointers);
nbuckets = (int) lbuckets;
dbatch = ceil(inner_rel_bytes / hash_table_bytes);
- dbatch = Min(dbatch, INT_MAX / 2);
+ dbatch = Min(dbatch, max_pointers);
minbatch = (int) dbatch;
nbatch = 2;
while (nbatch < minbatch)
double dbuckets;
dbuckets = ceil(ntuples / NTUP_PER_BUCKET);
- dbuckets = Min(dbuckets, INT_MAX);
+ dbuckets = Min(dbuckets, max_pointers);
nbuckets = (int) dbuckets;
nbatch = 1;
return;
/* safety check to avoid overflow */
- if (oldnbatch > INT_MAX / 2)
+ if (oldnbatch > Min(INT_MAX / 2, MaxAllocSize / (sizeof(void *) * 2)))
return;
nbatch = oldnbatch * 2;