diff options
Diffstat (limited to 'src/backend/executor/nodeHash.c')
| -rw-r--r-- | src/backend/executor/nodeHash.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c index 4bd332942d3..d2fae348466 100644 --- a/src/backend/executor/nodeHash.c +++ b/src/backend/executor/nodeHash.c @@ -398,6 +398,7 @@ ExecChooseHashTableSize(double ntuples, int tupwidth, bool useskew, long hash_table_bytes; long skew_table_bytes; long max_pointers; + long mppow2; int nbatch; int nbuckets; int i; @@ -465,7 +466,12 @@ ExecChooseHashTableSize(double ntuples, int tupwidth, bool useskew, */ max_pointers = (work_mem * 1024L) / sizeof(HashJoinTuple); max_pointers = Min(max_pointers, MaxAllocSize / sizeof(HashJoinTuple)); - /* also ensure we avoid integer overflow in nbatch and nbuckets */ + /* If max_pointers isn't a power of 2, must round it down to one */ + mppow2 = 1L << my_log2(max_pointers); + if (max_pointers != mppow2) + max_pointers = mppow2 / 2; + + /* Also ensure we avoid integer overflow in nbatch and nbuckets */ /* (this step is redundant given the current value of MaxAllocSize) */ max_pointers = Min(max_pointers, INT_MAX / 2); |