0001-Respect-MaxAllocSize-when-Parallel-Hash-increases-nb.patch

From 1f1909855a92be0786d304b8290c9dd4e97a49ba Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@enterprisedb.com>
Date: Thu, 7 Jun 2018 11:54:41 +1200
Subject: [PATCH] Respect MaxAllocSize when Parallel Hash increases nbucket.

Fix bug #15225 by making 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.

Author: Thomas Munro
Reported-by: Frits Jalvingh
Discussion: https://postgr.es/m/CAKhTGFWcOeOatgjqdYZRr9qfxFQ8vauzdw-42rd%2Bgm2S-PdZUg%40mail.gmail.com
---
 src/backend/executor/nodeHash.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 4f069d17fd8..e15bc44bca1 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -2820,7 +2820,9 @@ ExecParallelHashTupleAlloc(HashJoinTable hashtable, size_t size,
 			hashtable->batches[0].ntuples = 0;
 			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);
-- 
2.17.0