596efd27ed
distribution, by creating a special fast path for the (first few) most common values of the outer relation. Tuples having hashvalues matching the MCVs are effectively forced to be in the first batch, so that we never write them out to the batch temp files. Bryce Cutt and Ramon Lawrence, with some editorialization by me.
51 lines
1.8 KiB
C
51 lines
1.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* nodeHash.h
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* prototypes for nodeHash.c
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*
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*
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* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/executor/nodeHash.h,v 1.47 2009/03/21 00:04:40 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef NODEHASH_H
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#define NODEHASH_H
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#include "nodes/execnodes.h"
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extern int ExecCountSlotsHash(Hash *node);
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extern HashState *ExecInitHash(Hash *node, EState *estate, int eflags);
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extern TupleTableSlot *ExecHash(HashState *node);
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extern Node *MultiExecHash(HashState *node);
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extern void ExecEndHash(HashState *node);
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extern void ExecReScanHash(HashState *node, ExprContext *exprCtxt);
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extern HashJoinTable ExecHashTableCreate(Hash *node, List *hashOperators);
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extern void ExecHashTableDestroy(HashJoinTable hashtable);
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extern void ExecHashTableInsert(HashJoinTable hashtable,
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TupleTableSlot *slot,
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uint32 hashvalue);
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extern bool ExecHashGetHashValue(HashJoinTable hashtable,
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ExprContext *econtext,
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List *hashkeys,
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bool outer_tuple,
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bool keep_nulls,
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uint32 *hashvalue);
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extern void ExecHashGetBucketAndBatch(HashJoinTable hashtable,
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uint32 hashvalue,
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int *bucketno,
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int *batchno);
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extern HashJoinTuple ExecScanHashBucket(HashJoinState *hjstate,
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ExprContext *econtext);
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extern void ExecHashTableReset(HashJoinTable hashtable);
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extern void ExecChooseHashTableSize(double ntuples, int tupwidth, bool useskew,
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int *numbuckets,
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int *numbatches,
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int *num_skew_mcvs);
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extern int ExecHashGetSkewBucket(HashJoinTable hashtable, uint32 hashvalue);
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#endif /* NODEHASH_H */
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