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First cut at doing something reasonable with OR-of-ANDs WHERE

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conditions.  There are some pretty bogus heuristics in prepqual.c that
try to decide whether to output CNF or DNF format; they need to be replaced,
likely.  Right now the code is probably too willing to choose DNF form,
which might hurt performance in some cases that used to work OK.
But at least we have a foundation to build on.
This commit is contained in:
Tom Lane
1999-09-13 00:17:25 +00:00
parent b705fa3909
commit 43d32d3683
5 changed files with 269 additions and 21 deletions
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6
src/backend/optimizer/plan/planmain.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.43 1999/08/22 23:56:45 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.44 1999/09/13 00:17:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -75,9 +75,9 @@ query_planner(Query *root,
if (root->hasSubLinks)
qual = (List *) SS_process_sublinks((Node *) qual);
qual = cnfify((Expr *) qual, true);
qual = canonicalize_qual((Expr *) qual, true);
#ifdef OPTIMIZER_DEBUG
printf("After cnfify()\n");
printf("After canonicalize_qual()\n");
pprint(qual);
#endif