Good day,
I just stumbled across this peculiarity in PL/Perl today writing a method
to invoke Perl Regexes from a function: if a run-time error is raised in
an otherwise good function, the function will never run correctly again
until the connection to the database is reset. I poked around in the code
and it appears that it's because when elog() raises the ERROR, it doesn't
first take action to erase the system error message ($@) and consequently
every subsequent run has an error raised, even if it runs successfully.
For example:
-- This comparison works fine.
template1=# SELECT perl_re_match('test', 'test');perl_re_match
---------------t
(1 row)
-- This one dies, for obvious reasons.
template1=# SELECT perl_re_match('test', 't{1}+?');
ERROR: plperl: error from function: (in cleanup) Nested quantifiers
before HERE mark in regex m/t{1}+ << HERE ?/ at (eval 2) line 4.
-- This should work fine again, but we still have this error raised...!
template1=# SELECT perl_re_match('test', 'test');
ERROR: plperl: error from function: (in cleanup) Nested quantifiers
before HERE mark in regex m/t{1}+ << HERE ?/ at (eval 2) line 4.
I don't know if the following is the best way to solve it, but I got
around it by modifying the error report in this part of PL/Perl to be a
NOTICE, cleared the $@ variable, and then raised the fatal ERROR. A simple
three line patch to plperl.c follows, and is attached.
src/pl/plperl/plperl.c:
443c443,445
< elog(ERROR, "plperl: error from function: %s", SvPV(ERRSV, PL_na));
---
> elog(NOTICE, "plperl: error from function: %s", SvPV(ERRSV, PL_na));
> sv_setpv(perl_get_sv("@",FALSE),"");
> elog(ERROR, "plperl: error was fatal.");
Best Regards,
Jw.
--
John Worsley - lx@openvein.com
http://www.openvein.com/
