| From: | Mark Dilger <mark(dot)dilger(at)enterprisedb(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Andrew Dunstan <andrew(at)dunslane(dot)net>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Joel Jacobson <joel(at)compiler(dot)org> |
| Subject: | Re: Another regexp performance improvement: skip useless paren-captures |
| Date: | 2021-08-09 21:01:13 |
| Message-ID: | A099E4A8-4377-4C64-A98C-3DEDDC075502@enterprisedb.com |
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| Lists: | pgsql-hackers |
Tom,
I can still trigger the old bug for which we thought we'd pushed a fix. The test case below crashes on master (e12694523e7e4482a052236f12d3d8b58be9a22c), and also on the fixed version "Make regexp engine's backref-related compilation state more bulletproof." (cb76fbd7ec87e44b3c53165d68dc2747f7e26a9a).
Can you test if it crashes for you, too? I'm not sure I see why this one fails when millions of others pass.
The backtrace is still complaining about regc_nfa.c:1265:
+select regexp_split_to_array('', '(?:((?:q+))){0}(\1){0,0}?*[^]');
+server closed the connection unexpectedly
+ This probably means the server terminated abnormally
+ before or while processing the request.
+connection to server was lost
—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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