[Mediawiki-l] Extremely slow response after upgrade to 3.12.0

[Neil Bird]

   In a nutshell, I've upgraded a previously working 1.5.(1?) install to 
1.12.0.  It seemed to go smoothly, and everything's there with no 
discernible errors, but pages are taking some 20 s. to come back.

   I'm not running any caching, but there are 4 wikis on this [CentOS 5] box 
running under Apache virtual servers, one at least of which has been 1.12.0 
for a bit and doesn't show any slowness with no caching.

   I've compared the LocalSettings.php files for the OK one and my slow one, 
and there's nothing obviously different that might affect this.

   Bizarrely, we have a development box alongside the production one which 
ought to be identical (they actually both virtual boxes on the same hopst(s) 
just to confuse matters), and my wiki runs at a decent rate on that one. 
Same versions, I've copied the d/b across (mysqldump --add-drop-tables), and 
compared the entire 'wiki' subdirs.  No obvious diff.

   The only advertised diff. between the production box and the dev. one is 
that the production box uses SELinux.

   *Also*, I have found that I can ‘remove’ the speed problem by using 
“$wgUseDatabaseMessages = false;“ (from a google around the issue). 
However, the MediaWiki docs imply that this would be obviated by using 
caching, and I have tried memcached temporarily, and it seemed to make no 
difference at all.


   I'm now down to analysing a strace of a php session between the working 
wiki and mine.

   Just for completeness, here's a bit of my strace that displays a lag. 
Note that I can find no ref. to ‘Revision.php’ in the strace of the working 
one.  Also, just prio to this there's mention of ‘MediaWikiBagOStuf...’ and 
then ‘MessageCache::loa...’ in what I think is a channel to mysql.  There's 
no mention of MessageCache, bar one to the .php file, in the working strace.

   Does anyone have any ideas about what I can look at next?

   ----

time(NULL)                              = 1214560045
lstat64("/var", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat64("/var/www/fwwiki", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
lstat64("/var/www/fwwiki/wiki", {st_mode=S_IFDIR|0775, st_size=4096, ...}) = 0
lstat64("/var/www/fwwiki/wiki/includes", {st_mode=S_IFDIR|0775, 
st_size=12288, ...}) = 0
lstat64("/var/www/fwwiki/wiki/includes/Revision.php", {st_mode=S_IFREG|0664, 
st_size=22430, ...}) = 0
open("/var/www/fwwiki/wiki/includes/Revision.php", O_RDONLY) = 4
fstat64(4, {st_mode=S_IFREG|0664, st_size=22430, ...}) = 0
lseek(4, 0, SEEK_CUR)                   = 0
read(4, "<?php\n/**\n * @todo document\n */\n"..., 8192) = 8192
brk(0x8c54000)                          = 0x8c54000
read(4, "er      = isset( $row[\'user\']   "..., 8192) = 8192
read(4, "o external storage if required\n\t"..., 8192) = 6046
read(4, "", 8192)                       = 0
read(4, "", 8192)                       = 0
close(4)                                = 0
nanosleep({1, 213780000}, NULL)         = 0
<snip lots of these>
nanosleep({1, 70533000}, NULL)          = 0
access("/var/www/fwwiki/wiki/serialized/MessagesEn.ser", F_OK) = -1 ENOENT 
(No such file or directory)
access("/var/www/fwwiki/wiki/languages/messages/MessagesEn.php", F_OK) = 0
stat64("/var/www/fwwiki/wiki/languages/messages/MessagesEn.php", 
{st_mode=S_IFREG|0664, st_size=188674, ...}) = 0
time(NULL)                              = 1214560066


-- 
[neil at fnx ~]# rm -f .signature
[neil at fnx ~]# ls -l .signature
ls: .signature: No such file or directory
[neil at fnx ~]# exit