[CWB] mysql cache errors occurring recently
Hardie, Andrew
a.hardie at lancaster.ac.uk
Thu Apr 12 18:00:15 CEST 2018
It's controlled by the config setting $db_cache_size_limit . See admin manual, page 26.
It defaults to 6 GB which is usually plenty.
best
Andrew.
-----Original Message-----
From: cwb-bounces at sslmit.unibo.it [mailto:cwb-bounces at sslmit.unibo.it] On Behalf Of Jörg Knappen
Sent: 12 April 2018 16:57
To: Open source development of the Corpus WorkBench <cwb at sslmit.unibo.it>
Subject: Re: [CWB] mysql cache errors occurring recently
Andrew,
there are indeed a lot of saved catqueries on our server; so I
probably need to grow the cache, how do I do this?
Jörg
Quoting "Hardie, Andrew" <a.hardie at lancaster.ac.uk>:
> If all tables are properly tracked, then the oldest should be
> deleted whenever more space is needed. So the cache will rise to
> 99/100 % full, then stay at that level of fullness.
>
> (Before a new DB is created, a check is made for the cache being
> past its limit. The " DATABASE CACHE OVERLOAD " message appears if
> that process fails for any reason.)
>
> It's difficult for me to work out what the problem might be without
> actually being able to see your cache control window myself.
>
> One possibility is if your users have lots of categorised queries?
> These take up space in the DB cache, but cannot be deleted. If this
> is the problem, the solution is to grow the cache.
>
> You can look at the list of databases in cache for each corpus in
> the admin tools of that corpus - under "Cached databases" .
>
> best
>
> Andrew.
>
> -----Original Message-----
> From: cwb-bounces at sslmit.unibo.it
> [mailto:cwb-bounces at sslmit.unibo.it] On Behalf Of Jörg Knappen
> Sent: 12 April 2018 16:41
> To: Open source development of the Corpus WorkBench <cwb at sslmit.unibo.it>
> Subject: Re: [CWB] mysql cache errors occurring recently
>
> Andrew,
>
> thanks for the answer. I found the tool and there were indeed a few
> orphaned cache entries,
> but their total size was negligible. The cache is still 99% in use;
> how can I clear more of it?
>
> Jörg Knappen
>
> Quoting "Hardie, Andrew" <a.hardie at lancaster.ac.uk>:
>
>> 3 things.
>>
>> First, the function names/line numbers in the debug backtrace
>> suggest this is rather an old version of the code. So, you might
>> consider upgrading.
>>
>> Second, you might find that if you look on the "cache control" /
>> "database cache" page in the admin interface, it will tell you what
>> is wrong. (This is assuming that your version of the code is not too
>> old to have that tool!) One possibility is that you have a number of
>> orphaned database table records which make the cache look fuller
>> than it actually is. Deleting the orphan records would in that case
>> solve the problem.
>>
>> Third, when you get the " Too many database processes " error, you
>> can look under "Manage MySQL processes" again in the admin UI, and
>> delete records of zombie processes.
>>
>> best
>>
>> Andrew.
>>
>>
>> -----Original Message-----
>> From: cwb-bounces at sslmit.unibo.it
>> [mailto:cwb-bounces at sslmit.unibo.it] On Behalf Of Jörg Knappen
>> Sent: 12 April 2018 13:48
>> To: cwb at sslmit.unibo.it
>> Subject: [CWB] mysql cache errors occurring recently
>>
>> We run a cqpweb on Ubuntu 14.04 LTS using the following php version
>>
>>
>> PHP 5.5.9-1ubuntu4.24 (cli) (built: Mar 16 2018 12:41:43)
>> Copyright (c) 1997-2014 The PHP Group
>> Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies
>> with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies
>>
>>
>> and the mysql version
>>
>> mysql Ver 14.14 Distrib 5.5.59, for debian-linux-gnu (x86_64) using
>> readline 6.3
>>
>> We did not change cqpweb recently, nor did we anything but doing
>> reqular system upgrades using
>> apt-get upgrade.
>>
>> HOwever, when we try a frequency breakdown, the following error
>> appears (frst encountered about a week or so ago):
>>
>> CRITICAL ERROR - DATABASE CACHE OVERLOAD!
>>
>>
>>
>>
>>
>> CQPweb tried to clear database cache space but failed!
>>
>>
>>
>>
>>
>> Please report this error to the system administrator.
>>
>>
>> PHP debugging backtrace
>>
>> array(5) {
>> [1]=>
>> array(4) {
>> ["file"]=>
>> string(35) "/var/www/html/cqpweb/lib/db.inc.php"
>> ["line"]=>
>> int(581)
>> ["function"]=>
>> string(20) "exiterror_dboverload"
>> ["args"]=>
>> array(0) {
>> }
>> }
>> [2]=>
>> array(4) {
>> ["file"]=>
>> string(35) "/var/www/html/cqpweb/lib/db.inc.php"
>> ["line"]=>
>> int(95)
>> ["function"]=>
>> string(16) "delete_saved_dbs"
>> ["args"]=>
>> array(0) {
>> }
>> }
>> [3]=>
>> array(4) {
>> ["file"]=>
>> string(42) "/var/www/html/cqpweb/lib/breakdown.inc.php"
>> ["line"]=>
>> int(160)
>> ["function"]=>
>> string(9) "create_db"
>> ["args"]=>
>> array(6) {
>> [0]=>
>> &string(4) "sort"
>> [1]=>
>> &string(10) "fqa49mvvxx"
>> [2]=>
>> &string(12) "[word="des"]"
>> [3]=>
>> &string(0) ""
>> [4]=>
>> &string(0) ""
>> [5]=>
>> &string(0) ""
>> }
>> }
>> [4]=>
>> array(4) {
>> ["file"]=>
>> string(41) "/var/www/html/cqpweb/lib/redirect.inc.php"
>> ["line"]=>
>> int(73)
>> ["args"]=>
>> array(1) {
>> [0]=>
>> string(42) "/var/www/html/cqpweb/lib/breakdown.inc.php"
>> }
>> ["function"]=>
>> string(7) "require"
>> }
>> [5]=>
>> array(4) {
>> ["file"]=>
>> string(37) "/var/www/html/cqpweb/exe/redirect.php"
>> ["line"]=>
>> int(1)
>> ["args"]=>
>> array(1) {
>> [0]=>
>> string(41) "/var/www/html/cqpweb/lib/redirect.inc.php"
>> }
>> ["function"]=>
>> string(7) "require"
>> }
>> }
>>
>> and after a few more tries we finally reach the following error:
>>
>> Too many database processes!
>>
>> There are already 5 query sort databases being compiled.
>>
>> Please use the Back-button of your browser and try again in a few moments.
>>
>> Rebooting the server removes the latter error, but not the cache problem.
>>
>> What can be the cause of the cache problem and how can I remove it?
>>
>> Greetings from Saarbrücken,
>>
>> Jörg Knappen
>>
>>
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