diff options
Diffstat (limited to 'src/backend/access/hash/hashsort.c')
| -rw-r--r-- | src/backend/access/hash/hashsort.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/src/backend/access/hash/hashsort.c b/src/backend/access/hash/hashsort.c index 0e0f3937117..41d615df8b5 100644 --- a/src/backend/access/hash/hashsort.c +++ b/src/backend/access/hash/hashsort.c @@ -37,7 +37,15 @@ struct HSpool { Tuplesortstate *sortstate; /* state data for tuplesort.c */ Relation index; - uint32 hash_mask; /* bitmask for hash codes */ + + /* + * We sort the hash keys based on the buckets they belong to. Below masks + * are used in _hash_hashkey2bucket to determine the bucket of given hash + * key. + */ + uint32 high_mask; + uint32 low_mask; + uint32 max_buckets; }; @@ -56,11 +64,12 @@ _h_spoolinit(Relation heap, Relation index, uint32 num_buckets) * num_buckets buckets in the index, the appropriate mask can be computed * as follows. * - * Note: at present, the passed-in num_buckets is always a power of 2, so - * we could just compute num_buckets - 1. We prefer not to assume that - * here, though. + * NOTE : This hash mask calculation should be in sync with similar + * calculation in _hash_init_metabuffer. */ - hspool->hash_mask = (((uint32) 1) << _hash_log2(num_buckets)) - 1; + hspool->high_mask = (((uint32) 1) << _hash_log2(num_buckets + 1)) - 1; + hspool->low_mask = (hspool->high_mask >> 1); + hspool->max_buckets = num_buckets - 1; /* * We size the sort area as maintenance_work_mem rather than work_mem to @@ -69,7 +78,9 @@ _h_spoolinit(Relation heap, Relation index, uint32 num_buckets) */ hspool->sortstate = tuplesort_begin_index_hash(heap, index, - hspool->hash_mask, + hspool->high_mask, + hspool->low_mask, + hspool->max_buckets, maintenance_work_mem, false); @@ -122,7 +133,9 @@ _h_indexbuild(HSpool *hspool, Relation heapRel) #ifdef USE_ASSERT_CHECKING uint32 lasthashkey = hashkey; - hashkey = _hash_get_indextuple_hashkey(itup) & hspool->hash_mask; + hashkey = _hash_hashkey2bucket(_hash_get_indextuple_hashkey(itup), + hspool->max_buckets, hspool->high_mask, + hspool->low_mask); Assert(hashkey >= lasthashkey); #endif |