Wikimedia Bugzilla is closed!

it seems to have something to do with the messages loading from the database and
its apparently not plain volume of text

[18:42] <plugwash> mysql> select sum(length(cur_text)) from cur;
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> | sum(length(cur_text)) |
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> |                 54795 |
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> 1 row in set (0.00 sec)
[18:42] <plugwash> mysql> select sum(length(cur_text)) from cur where
cur_namespace=8;
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> | sum(length(cur_text)) |
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> |                 44296 |
[18:42] <plugwash> +-----------------------+
[18:42] <plugwash> 1 row in set (0.00 sec)
<--some other chat on other topics snipped-->
[18:43] <plugwash> does that look normal to you?
[18:43] <dammit> yes, absolutely normal.

commenting out the following lines in the get function of
includes/MessageCache.php seems to make it work

if( $this->mDeferred ) {
        $this->load();
}

(In reply to comment #2)
> commenting out the following lines in the get function of
> includes/MessageCache.php seems to make it work

Will this Problem be solved in Mediawiki 1.4.1? On my server is also a debian
woody running. The Problem is exactly the same as described before.

Another person ran into this on IRC. I was able to replicate the 
problem on a local Debian Woody installation with a partial copy of 
their database, and isolated the giant memory allocation to the 
gzinflate() call in SqlBagOStuff::_unserialize() when loading the 
objectcache record for the messages.

This seems to be a bug in either the old version of PHP or the old 
version of zlib in Woody; if I dump the compressed data and try to 
read it back with a minimal PHP script, it fails this way on Woody 
(claims to want to allocate a huge amount of memory, hitting the 8mb 
memory limit) but works fine on a modern Ubuntu install with that 
same 8mb memory limit.

As a workaround, you can disable compression in the object cache; 
comment out the bits to use gzdeflate and gzinflate and let it deal 
in raw text.

Created attachment 582 [details]
Test case

This tarball, created by brion, demonstrates the bug.
Known to fail in debian woody and succeed in at least ubuntu breezy.

Upstream fix.

Debian 3.1 out since June 6th 2005, that should solve the issue.

changing resoloution to WONTFIX since this bug hasn't actually been fixed by us
its just that woody is no longer worth caring about.