Re: Patch: add conversion from pg_wchar to multibyte

Hi Alexander,

Perhaps I'm too early with these tests, but FWIW I reran my earlier test program against three
instances. (the patches compiled fine, and make check was without problem).

-- 3 instances:
HEAD port 6542
trgm_regex port 6547 HEAD + trgm-regexp patch (22 Nov 2011) [1]
trgm_regex_wchar2mb port 6549 HEAD + trgm-regexp + wchar2mb patch (23 Apr 2012) [2]

[1] http://archives.postgresql.org/pgsql-hackers/2011-11/msg01297.php
[2] http://archives.postgresql.org/pgsql-hackers/2012-04/msg01095.php

-- table sizes:
azjunk4 10^4 rows 1 MB
azjunk5 10^5 rows 11 MB
azjunk6 10^6 rows 112 MB
azjunk7 10^7 rows 1116 MB

for table creation/structure, see:
[3] http://archives.postgresql.org/pgsql-hackers/2012-01/msg01094.php

Results for three instances with 4 repetitions per instance are attached.

Although the regexes I chose are somewhat arbitrary, it does show some of the good, the bad and
the ugly of the patch(es). (Also: I've limited the tests to a range of 'workable' regexps, i.e.
avoiding unbounded regexps)

hth (and thanks, great work!),

Erik Rijkers