diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 3510a4247c..b052b3b044 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -832,7 +832,10 @@ ExecChooseHashTableSize(double ntuples, int tupwidth, bool useskew,
 		 * overhead for the hash code, pointer to the next tuple, etc.
 		 */
 		bucket_size = (tupsize * NTUP_PER_BUCKET + sizeof(HashJoinTuple));
-		sbuckets = pg_nextpower2_size_t(hash_table_bytes / bucket_size);
+		if (hash_table_bytes <= bucket_size)
+			sbuckets = 1;		/* avoid pg_nextpower2_size_t(0) */
+		else
+			sbuckets = pg_nextpower2_size_t(hash_table_bytes / bucket_size);
 		sbuckets = Min(sbuckets, max_pointers);
 		nbuckets = (int) sbuckets;
 		nbuckets = pg_nextpower2_32(nbuckets);