Tom Lane 628cbb50ba Re-implement extraction of fixed prefixes from regular expressions. ... To generate btree-indexable conditions from regex WHERE conditions (such as WHERE indexed_col ~ '^foo'), we need to be able to identify any fixed prefix that a regex might have; that is, find any string that must be a prefix of all strings satisfying the regex. We used to do that with entirely ad-hoc code that looked at the source text of the regex. It didn't know very much about regex syntax, which mostly meant that it would fail to identify some optimizable cases; but Viktor Rosenfeld reported that it would produce actively wrong answers for quantified parenthesized subexpressions, such as '^(foo)?bar'. Rather than trying to extend the ad-hoc code to cover this, let's get rid of it altogether in favor of identifying prefixes by examining the compiled form of a regex. To do this, I've added a new entry point "pg_regprefix" to the regex library; hopefully it is defined in a sufficiently general fashion that it can remain in the library when/if that code gets split out as a standalone project. Since this bug has been there for a very long time, this fix needs to get back-patched. However it depends on some other recent commits (particularly the addition of wchar-to-database-encoding conversion), so I'll commit this separately and then go to work on back-porting the necessary fixes.		2012-07-10 14:54:37 -04:00
..
data	Fix GIN to support null keys, empty and null items, and full index scans.	2011-01-07 19:16:24 -05:00
expected	Re-implement extraction of fixed prefixes from regular expressions.	2012-07-10 14:54:37 -04:00
input	Fix error message for COMMENT/SECURITY LABEL ON COLUMN xxx IS 'yyy'	2012-05-22 11:23:36 -04:00
output	Reduce messages about implicit indexes and sequences to DEBUG1.	2012-07-04 20:35:29 -04:00
sql	Re-implement extraction of fixed prefixes from regular expressions.	2012-07-10 14:54:37 -04:00
.gitignore	Convert cvsignore to gitignore, and add .gitignore for build targets.	2010-09-22 12:57:04 +02:00
GNUmakefile	pg_regress: Use target-specific variable instead of overriding make rule	2012-02-07 22:42:19 +02:00
Makefile
parallel_schedule	Fix regex back-references that are directly quantified with *.	2012-02-20 00:52:33 -05:00
pg_regress_main.c	pg_regress: Replace exit_nicely() with exit() plus atexit() hook	2012-01-02 22:09:25 +02:00
pg_regress.c	Run pgindent on 9.2 source tree in preparation for first 9.3	2012-06-10 15:20:04 -04:00
pg_regress.h	pg_regress: Replace exit_nicely() with exit() plus atexit() hook	2012-01-02 22:09:25 +02:00
regress.c	Redesign the plancache mechanism for more flexibility and efficiency.	2011-09-16 00:43:52 -04:00
regressplans.sh
resultmap	Enable compiling with the mingw-w64 32 bit compiler.	2011-12-10 15:35:41 -05:00
serial_schedule	Fix regex back-references that are directly quantified with *.	2012-02-20 00:52:33 -05:00
standby_schedule	Remove cvs keywords from all files.	2010-09-20 22:08:53 +02:00