mirror of https://github.com/postgres/postgres
Bruce Momjian
25 years ago
parent
648029ec2e
commit
b36d31030b
@ -1,43 +0,0 @@ |
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#
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# $Header: /cvsroot/pgsql/contrib/likeplanning/Attic/Makefile,v 1.1 2000/06/15 19:04:56 momjian Exp $
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#
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TOPDIR=../..
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include ../Makefile.global |
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NAME =
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PROGRAM =
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OBJS =
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DOCS = likeplanning.doc
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SQLS = disablelike.sql enablelike.sql
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BINS =
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EXAMPLES=
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MODS =
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OTHER_CLEAN =
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all:: |
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install: install_doc install_sql |
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install_doc: |
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for inst_file in $(DOCS); do \
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$(INSTALL) $(INSTL_LIB_OPTS) $$inst_file $(CONTRIB_DOCDIR); \
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done
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install_sql: |
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for inst_file in $(SQLS); do \
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$(INSTALL) $(INSTL_LIB_OPTS) $$inst_file $(CONTRIB_SQLDIR); \
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done
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depend dep: |
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$(CC) -MM -MG $(CFLAGS) *.c > depend
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clean: |
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$(RM) *~ $(OBJS) $(MODS) $(PROGRAM) depend $(OTHER_CLEAN) core log
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ifeq (depend,$(wildcard depend)) |
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include depend |
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endif |
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@ -1,44 +0,0 @@ |
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This directory contains two SQL scripts that control use of some new |
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code for planning/optimizing queries containing LIKE and |
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regular-expression operators. This code was added to Postgres 7.0 late in |
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beta test, and it hasn't gotten enough testing to warrant turning it on by |
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default in release 7.0 (although it probably will become default in 7.1). |
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So, here are some scripts to enable and disable it. You may want to run |
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these scripts if you have problems with the planner choosing bad plans for |
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queries involving LIKE or regexps in WHERE clauses. |
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HOW TO USE THE SCRIPTS |
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---------------------- |
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Both scripts must be run as the Postgres superuser. The easiest |
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way to run an SQL script is |
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psql -f scriptfile databasename |
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or you can start psql interactively and enter |
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\i scriptfile |
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enablelike.sql enables use of the new planning code in the database in |
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which it is run. If you run it in template1, all subsequently-created |
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databases will use the new code by default. |
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disablelike.sql reverts to the old planning code for LIKE, in the database |
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in which it is run. If you run it in template1, all subsequently-created |
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databases will use the old code by default. |
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WHAT IT DOES |
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------------ |
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These scripts install (or disable) new code for "selectivity estimation" |
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of LIKE and regexp operators. Selectivity estimation determines the |
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estimated number of rows produced by a query or subquery, and that in turn |
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determines the kind of plan the planner will use. The old selectivity |
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estimator ignored the pattern being searched for and just produced the |
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same estimate as for an "=" operator, which of course was usually too low |
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for a wildcard match. The new code has some knowledge of pattern matching |
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rules and generates an estimate based on the number of fixed characters and |
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wildcards present in the pattern. Also, if the pattern has a fixed prefix |
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that must be matched (such as LIKE 'foo%' or ~ '^foo'), an appropriate |
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range-query selectivity estimate is produced and factored into the result. |
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If you want to look at the code itself, see src/backend/utils/adt/selfuncs.c. |
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@ -1,39 +0,0 @@ |
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-- This script disables use of the new LIKE-related selectivity estimation |
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-- functions, which are a little too new to be enabled by default in 7.0. |
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-- You can enable them again by running enablelike.sql. |
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-- Use of the functions will be disabled only in those databases you |
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-- run this script in. If you run it in template1, |
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-- all subsequently-created databases will not use the functions. |
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-- Be sure to run the script as the Postgres superuser! |
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UPDATE pg_operator SET |
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oprrest = 'eqsel'::regproc, |
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oprjoin = 'eqjoinsel'::regproc |
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WHERE oprrest = 'regexeqsel'::regproc; |
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UPDATE pg_operator SET |
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oprrest = 'eqsel'::regproc, |
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oprjoin = 'eqjoinsel'::regproc |
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WHERE oprrest = 'icregexeqsel'::regproc; |
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UPDATE pg_operator SET |
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oprrest = 'eqsel'::regproc, |
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oprjoin = 'eqjoinsel'::regproc |
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WHERE oprrest = 'likesel'::regproc; |
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UPDATE pg_operator SET |
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oprrest = 'neqsel'::regproc, |
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oprjoin = 'neqjoinsel'::regproc |
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WHERE oprrest = 'regexnesel'::regproc; |
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UPDATE pg_operator SET |
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oprrest = 'neqsel'::regproc, |
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oprjoin = 'neqjoinsel'::regproc |
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WHERE oprrest = 'icregexnesel'::regproc; |
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UPDATE pg_operator SET |
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oprrest = 'neqsel'::regproc, |
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oprjoin = 'neqjoinsel'::regproc |
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WHERE oprrest = 'nlikesel'::regproc; |
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@ -1,39 +0,0 @@ |
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-- This script enables use of the new LIKE-related selectivity estimation |
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-- functions, which are a little too new to be enabled by default in 7.0. |
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-- You can disable them again by running disablelike.sql. |
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-- Use of the functions will be enabled only in those databases you |
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-- run this script in. If you run it in template1, |
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-- all subsequently-created databases will use the functions. |
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-- Be sure to run the script as the Postgres superuser! |
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UPDATE pg_operator SET |
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oprrest = 'regexeqsel'::regproc, |
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oprjoin = 'regexeqjoinsel'::regproc |
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WHERE oprrest = 'eqsel'::regproc AND oprname = '~'; |
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UPDATE pg_operator SET |
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oprrest = 'icregexeqsel'::regproc, |
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oprjoin = 'icregexeqjoinsel'::regproc |
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WHERE oprrest = 'eqsel'::regproc AND oprname = '~*'; |
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UPDATE pg_operator SET |
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oprrest = 'likesel'::regproc, |
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oprjoin = 'likejoinsel'::regproc |
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WHERE oprrest = 'eqsel'::regproc AND oprname = '~~'; |
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UPDATE pg_operator SET |
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oprrest = 'regexnesel'::regproc, |
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oprjoin = 'regexnejoinsel'::regproc |
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WHERE oprrest = 'neqsel'::regproc AND oprname = '!~'; |
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UPDATE pg_operator SET |
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oprrest = 'icregexnesel'::regproc, |
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oprjoin = 'icregexnejoinsel'::regproc |
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WHERE oprrest = 'neqsel'::regproc AND oprname = '!~*'; |
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UPDATE pg_operator SET |
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oprrest = 'nlikesel'::regproc, |
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oprjoin = 'nlikejoinsel'::regproc |
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WHERE oprrest = 'neqsel'::regproc AND oprname = '!~~'; |
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