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Add an at-least-marginally-plausible method of estimating the number

of groups produced by GROUP BY.  This improves the accuracy of planning
estimates for grouped subselects, and is needed to check whether a
hashed aggregation plan risks memory overflow.
This commit is contained in:
Tom Lane
2002-11-19 23:22:00 +00:00
parent 54cb1db6cf
commit b60be3f2f8
11 changed files with 454 additions and 75 deletions

View File

@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.218 2002/11/15 02:50:06 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.219 2002/11/19 23:21:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1865,8 +1865,8 @@ _copyQuery(Query *from)
/*
* We do not copy the planner internal fields: base_rel_list,
* other_rel_list, join_rel_list, equi_key_list, query_pathkeys. Not
* entirely clear if this is right?
* other_rel_list, join_rel_list, equi_key_list, query_pathkeys,
* hasJoinRTEs. Not entirely clear if this is right?
*/
return newnode;