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Correct oversight in hashjoin cost estimation: nodeHash sizes its hash

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table for an average of NTUP_PER_BUCKET tuples/bucket, but cost_hashjoin
was assuming a target load of one tuple/bucket.  This was causing a
noticeable underestimate of hashjoin costs.
This commit is contained in:
Tom Lane
2000-04-18 05:43:02 +00:00
parent 24864d048e
commit 25442d8d2f
3 changed files with 16 additions and 8 deletions
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3
src/backend/executor/nodeHash.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* $Id: nodeHash.c,v 1.44 2000/01/26 05:56:22 momjian Exp $
* $Id: nodeHash.c,v 1.45 2000/04/18 05:43:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -221,7 +221,6 @@ ExecEndHash(Hash *node)
* create a hashtable in shared memory for hashjoin.
* ----------------------------------------------------------------
*/
#define NTUP_PER_BUCKET 10
#define FUDGE_FAC 2.0
HashJoinTable