diff options
Diffstat (limited to 'src/backend/executor')
| -rw-r--r-- | src/backend/executor/nodeHash.c | 12 | ||||
| -rw-r--r-- | src/backend/executor/nodeHashjoin.c | 19 |
2 files changed, 21 insertions, 10 deletions
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c index c4236f5fcc4..5beb6359a83 100644 --- a/src/backend/executor/nodeHash.c +++ b/src/backend/executor/nodeHash.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.86 2004/08/29 04:12:31 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.87 2004/09/22 19:13:49 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -32,8 +32,8 @@ /* ---------------------------------------------------------------- * ExecHash * - * build hash table for hashjoin, all do partitioning if more - * than one batches are required. + * build hash table for hashjoin, doing partitioning if more + * than one batch is required. * ---------------------------------------------------------------- */ TupleTableSlot * @@ -81,6 +81,7 @@ ExecHash(HashState *node) slot = ExecProcNode(outerNode); if (TupIsNull(slot)) break; + hashtable->hashNonEmpty = true; econtext->ecxt_innertuple = slot; ExecHashTableInsert(hashtable, econtext, hashkeys); ExecClearTuple(slot); @@ -189,7 +190,7 @@ ExecEndHash(HashState *node) /* ---------------------------------------------------------------- * ExecHashTableCreate * - * create a hashtable in shared memory for hashjoin. + * create an empty hashtable data structure for hashjoin. * ---------------------------------------------------------------- */ HashJoinTable @@ -226,12 +227,13 @@ ExecHashTableCreate(Hash *node, List *hashOperators) * The hashtable control block is just palloc'd from the executor's * per-query memory context. */ - hashtable = (HashJoinTable) palloc(sizeof(HashTableData)); + hashtable = (HashJoinTable) palloc(sizeof(HashJoinTableData)); hashtable->nbuckets = nbuckets; hashtable->totalbuckets = totalbuckets; hashtable->buckets = NULL; hashtable->nbatch = nbatch; hashtable->curbatch = 0; + hashtable->hashNonEmpty = false; hashtable->innerBatchFile = NULL; hashtable->outerBatchFile = NULL; hashtable->innerBatchSize = NULL; diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c index 53215be6e91..294f481cdf5 100644 --- a/src/backend/executor/nodeHashjoin.c +++ b/src/backend/executor/nodeHashjoin.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.65 2004/09/17 18:28:53 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.66 2004/09/22 19:13:49 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -128,6 +128,17 @@ ExecHashJoin(HashJoinState *node) (void) ExecProcNode((PlanState *) hashNode); /* + * If the inner relation is completely empty, and we're not doing + * an outer join, we can quit without scanning the outer relation. + */ + if (!hashtable->hashNonEmpty && node->js.jointype != JOIN_LEFT) + { + ExecHashTableDestroy(hashtable); + node->hj_HashTable = NULL; + return NULL; + } + + /* * Open temp files for outer batches, if needed. Note that file * buffers are palloc'd in regular executor context. */ @@ -138,10 +149,8 @@ ExecHashJoin(HashJoinState *node) } /* - * Now get an outer tuple and probe into the hash table for matches + * run the hash join process */ - outerTupleSlot = node->js.ps.ps_OuterTupleSlot; - for (;;) { /* @@ -226,7 +235,7 @@ ExecHashJoin(HashJoinState *node) * Only the joinquals determine MatchedOuter status, but all * quals must pass to actually return the tuple. */ - if (ExecQual(joinqual, econtext, false)) + if (joinqual == NIL || ExecQual(joinqual, econtext, false)) { node->hj_MatchedOuter = true; |