Horton

Re: Another regexp performance improvement: skip useless paren-captures

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mark Dilger <mark.dilger@enterprisedb.com>
Cc: Andrew Dunstan <andrew@dunslane.net>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Joel Jacobson <joel@compiler.org>
Date: 2021-08-08T22:28:13Z
Lists: pgsql-hackers 
Mark Dilger <mark.dilger@enterprisedb.com> writes:
> I have applied your latest patch and do not see any problems with it.  All my tests pass with no asserts and with no differences in results vs. master.  This is a test suite of nearly 1.5 million separate regular expressions.

Cool, thanks.  I also tried your millions-of-random-regexps script
and didn't find any difference between the results from HEAD and
those from the v3 patch.

			regards, tom lane

Commits

  1. Fix regexp misbehavior with capturing parens inside "{0}".

  2. Let regexp_replace() make use of REG_NOSUB when feasible.

  3. Fix bogus assertion in BootstrapModeMain().

  4. Avoid determining regexp subexpression matches, when possible.

  5. Check the size in COPY_POINTER_FIELD

  6. Make regexp engine's backref-related compilation state more bulletproof.