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Tom Lane 78a843f119 Improve regex compiler's arc moving/copying logic.
The functions moveins(), copyins(), moveouts(), copyouts() are
required to preserve the invariant that there are no duplicate arcs in
the regex's NFA.  Spencer's original implementation of them was O(N^2)
since it checked separately for a match to each source arc.  In commit
579840ca0 I improved that by adding sort/merge logic to be used if
more than a few arcs are to be moved/copied.  However, I now realize
that that missed a bet.  At many call sites, the target state is newly
made and cannot have any existing in-arcs (respectively out-arcs)
that could be duplicates.  So spending any cycles at all on checking
for duplicates is wasted effort; in these cases we can just blindly
move/copy all the source arcs.  Add code paths to do that.

It turns out that for copyins()/copyouts(), *all* the call sites have
this property, making all the "improved" logic in them flat out
unreachable.  Perhaps we'll need the full capability again someday,
so I just #ifdef'd those paths out rather than removing them entirely.

In passing, add a few test cases to improve code coverage in this
area as well as in regc_locale.c/regc_pg_locale.c.

Discussion: https://postgr.es/m/810272.1629064063@sss.pgh.pa.us
2021-08-17 12:00:02 -04:00
config Remove configure-time thread safety checking (thread_test.c). 2021-07-24 12:16:39 -04:00
contrib Fix failure of btree_gin indexscans with "char" type and </<= operators. 2021-08-10 18:10:29 -04:00
doc doc: \123 and \x12 escapes in COPY are in database encoding. 2021-08-17 10:00:06 +03:00
src Improve regex compiler's arc moving/copying logic. 2021-08-17 12:00:02 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Add pgindent commit to git-blame-ignore-revs file. 2021-06-28 09:22:24 -07:00
.gitattributes gitattributes: Add new entry to silence whitespace error 2021-06-05 07:57:31 +02:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
aclocal.m4 Remove configure-time probe for DocBook DTD. 2020-11-30 15:24:13 -05:00
configure Remove configure-time thread safety checking (thread_test.c). 2021-07-24 12:16:39 -04:00
configure.ac Remove configure-time thread safety checking (thread_test.c). 2021-07-24 12:16:39 -04:00
COPYRIGHT Update copyright for 2021 2021-01-02 13:06:25 -05:00
GNUmakefile.in add missing tag from commit b8c4261e5e 2021-07-01 15:47:46 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Don't unset MAKEFLAGS in non-GNU Makefile. 2019-06-25 09:36:21 +12:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00

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:

	https://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.  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
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.