mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2025-02-05 19:09:58 +08:00
Code Issues Packages Projects Releases Wiki Activity
34,188 Commits 37 Branches 638 Tags 434 MiB
C 85.5%
PLpgSQL 5.9%
Perl 4.2%
Yacc 1.3%
Makefile 0.7%
Other 2.2%
1faf866ace
Go to file
Tom Lane 1faf866ace Fix logical errors in tsquery selectivity estimation for prefix queries. 
I made multiple errors in commit 97532f7c29,
stemming mostly from failure to think about the available frequency data
as being element frequencies not value frequencies (so that occurrences of
different elements are not mutually exclusive).  This led to sillinesses
such as estimating that "word" would match more rows than "word:*".

The choice to clamp to a minimum estimate of DEFAULT_TS_MATCH_SEL also
seems pretty ill-considered in hindsight, as it would frequently result in
an estimate much larger than the available data suggests.  We do need some
sort of clamp, since a pattern not matching any of the MCELEMs probably
still needs a selectivity estimate of more than zero.  I chose instead to
clamp to at least what a non-MCELEM word would be estimated as, preserving
the property that "word:*" doesn't get an estimate less than plain "word",
whether or not the word appears in MCELEM.

Per investigation of a gripe from Bill Martin, though I suspect that his
example case actually isn't even reaching the erroneous code.

Back-patch to 9.1 where this code was introduced.
2012-09-11 21:23:20 -04:00
config Also check for Python platform-specific include directory 2012-08-29 23:05:35 -04:00
contrib In pg_upgrade, try a few times to open a log file. 2012-09-05 23:14:49 -04:00
doc Fix typo: lexemes misspelled in full text search docs. 2012-09-11 19:46:17 -05:00
src Fix logical errors in tsquery selectivity estimation for prefix queries. 2012-09-11 21:23:20 -04:00
.gitignore
aclocal.m4
configure Make configure probe for mbstowcs_l as well as wcstombs_l. 2012-08-31 14:17:56 -04:00
configure.in Make configure probe for mbstowcs_l as well as wcstombs_l. 2012-08-31 14:17:56 -04:00
COPYRIGHT
GNUmakefile.in Make init-po and update-po recursive make targets 2012-06-29 14:01:54 +03:00
Makefile
README
README.git

README 

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	http://www.postgresql.org/download

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Changes between all PostgreSQL releases are recorded in the
file HISTORY.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
http://www.postgresql.org/download/.  For more information look at our
web site located at http://www.postgresql.org/.