diff options
Diffstat (limited to 'src/backend/optimizer/prep/_deadcode/prepkeyset.c')
| -rw-r--r-- | src/backend/optimizer/prep/_deadcode/prepkeyset.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/src/backend/optimizer/prep/_deadcode/prepkeyset.c b/src/backend/optimizer/prep/_deadcode/prepkeyset.c index b67431716fb..9de8ebb6c7f 100644 --- a/src/backend/optimizer/prep/_deadcode/prepkeyset.c +++ b/src/backend/optimizer/prep/_deadcode/prepkeyset.c @@ -1,7 +1,7 @@ /*------------------------------------------------------------------------- * * prepkeyset.c - * Special preperation for keyset queries. + * Special preparation for keyset queries (KSQO). * * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California @@ -14,12 +14,6 @@ #include "postgres.h" #include "optimizer/planmain.h" -/* - * Node_Copy - * a macro to simplify calling of copyObject on the specified field - */ -#define Node_Copy(from, newnode, field) newnode->field = copyObject(from->field) - bool _use_keyset_query_optimizer = FALSE; #ifdef ENABLE_KEY_SET_QUERY @@ -55,13 +49,20 @@ static int TotalExpr; * a HAVING, or a GROUP BY. It must be a single table and have KSQO * set to 'on'. * - * The primary use of this transformation is to avoid the exponrntial + * The primary use of this transformation is to avoid the exponential * memory consumption of cnfify() and to make use of index access * methods. * * daveh@insightdist.com 1998-08-31 * * May want to also prune out duplicate terms. + * + * XXX: this code is currently not compiled because it has not been + * updated to work with the re-implementation of UNION/INTERSECT/EXCEPT + * in PostgreSQL 7.1. However, it is of questionable value in any + * case, because it changes the semantics of the original query: + * UNION will add an implicit SELECT DISTINCT, which might change + * the results that are returned. **********************************************************************/ void transformKeySetQuery(Query *origNode) |