Limit Parallel Hash's bucket array to MaxAllocSize.

macdice · macdice · commit 86a2218eb00e · 2018-06-10T20:30:25.000+12:00
Make sure that we don't exceed MaxAllocSize when increasing the number of buckets. Perhaps later we'll remove that limit and use DSA_ALLOC_HUGE, but for now just prevent further increases like the non-parallel code. This change avoids the error from bug report #15225. Author: Thomas Munro Reviewed-By: Tom Lane Reported-by: Frits Jalvingh Discussion: https://postgr.es/m/152802081668.26724.16985037679312485972%40wrigleys.postgresql.org
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
@@ -2818,9 +2818,12 @@ ExecParallelHashTupleAlloc(HashJoinTable hashtable, size_t size,
 		{
 			hashtable->batches[0].shared->ntuples += hashtable->batches[0].ntuples;
 			hashtable->batches[0].ntuples = 0;
+			/* Guard against integer overflow and alloc size overflow */
 			if (hashtable->batches[0].shared->ntuples + 1 >
 				hashtable->nbuckets * NTUP_PER_BUCKET &&
-				hashtable->nbuckets < (INT_MAX / 2))
+				hashtable->nbuckets < (INT_MAX / 2) &&
+				hashtable->nbuckets * 2 <=
+				MaxAllocSize / sizeof(dsa_pointer_atomic))
 			{
 				pstate->growth = PHJ_GROWTH_NEED_MORE_BUCKETS;
 				LWLockRelease(&pstate->lock);

Original file line number	Diff line number	Diff line change
`@@ -2818,9 +2818,12 @@ ExecParallelHashTupleAlloc(HashJoinTable hashtable, size_t size,`
`2818`	`2818`	`{`
`2819`	`2819`	`hashtable->batches[0].shared->ntuples += hashtable->batches[0].ntuples;`
`2820`	`2820`	`hashtable->batches[0].ntuples = 0;`
	`2821`	`+ /* Guard against integer overflow and alloc size overflow */`
`2821`	`2822`	`if (hashtable->batches[0].shared->ntuples + 1 >`
`2822`	`2823`	`hashtable->nbuckets * NTUP_PER_BUCKET &&`
`2823`		`- hashtable->nbuckets < (INT_MAX / 2))`
	`2824`	`+ hashtable->nbuckets < (INT_MAX / 2) &&`
	`2825`	`+ hashtable->nbuckets * 2 <=`
	`2826`	`+ MaxAllocSize / sizeof(dsa_pointer_atomic))`
`2824`	`2827`	`{`
`2825`	`2828`	`pstate->growth = PHJ_GROWTH_NEED_MORE_BUCKETS;`
`2826`	`2829`	`LWLockRelease(&pstate->lock);`