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Upgrade cost estimation for joins, per discussion with Bradley Baetz.

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Try to model the effect of rescanning input tuples in mergejoins;
account for JOIN_IN short-circuiting where appropriate.  Also, recognize
that mergejoin and hashjoin clauses may now be more than single operator
calls, so we have to charge appropriate execution costs.
This commit is contained in:
Tom Lane
2003-01-27 20:51:54 +00:00
parent b2773d4099
commit 70fba70430
10 changed files with 360 additions and 189 deletions
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4
src/backend/utils/adt/selfuncs.c
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@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.129 2003/01/24 03:58:43 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.130 2003/01/27 20:51:54 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2043,6 +2043,8 @@ estimate_num_groups(Query *root, List *groupExprs, double input_rows)
varinfos = newvarinfos;
} while (varinfos != NIL);
numdistinct = ceil(numdistinct);
/* Guard against out-of-range answers */
if (numdistinct > input_rows)
numdistinct = input_rows;