| Subject: | TRACE performance issue related to regular expression |
| Date: | Wed, 30 May 2007 14:09:49 +0200 (CEST) |
| To: | bug-Tangram [...] rt.cpan.org |
| From: | Mark Lawrence <nomad [...] null.net> |
Hi,
Occasionally (took me ages to track down) I've had a huge slowdown (of the
order of half a second) with certain queries when TANGRAM::TRACE and
TANGRAM::DEBUG_LEVEL were set.
I narrowed it down to the debugging statement at
Tangram/Relational/PolySelectTemplate.pm:253
The attached program duplicates that statement with the input being
generated by my program to get the execution times. When I run it on my
Fujitsu Lifebook S2110 (about 1 year old) I get the following timings:
0.0017859935760498
0.545166015625 <========== WT?
0.000358104705810547
0.00082087516784668
0.00049901008605957
0.000385046005249023
I'm guess that this is actually some issue with the Perl regular
expression engine, not Tangram. However if there are any RE gurus who know
what's going on, and more importantly how to rewrite this expression to
stop this from happening I'd appreciate it. Have to comment out that
expression for now... (or have no debugging).
The query that generates this input looks like this:
my $rem = $self->{storage}->remote('Node');
my $remt = $self->{storage}->remote('NodeT');
my $filter = (
(($rem->{parent} == $self->{root}) | ($rem->{path} == '/'))
& ($rem->{menuitem} > 0)
& ($rem->{published} > 0)
& (($remt->{transof} == $rem->{id}) &
(($rem->{visnotrans} > 0) | ($remt->{lang} eq $self->{lang})))
);
my @children = $self->{storage}->select($rem,
filter => $filter,
distinct => 1,
);
Cheers,
Mark.
--
Mark Lawrence
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