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Consistent fatal timeout when visiting Special:Log default view for some users
Closed, ResolvedPublicPRODUCTION ERROR

Description

When I visit https://en.wikipedia.org/wiki/Special:Log/MZMcBride I'm getting a MediaWiki internal error.

MediaWiki internal error.

Original exception: [4e8e27cb-9d12-4ecc-b5ad-98e89a464988] 2022-03-04 23:33:39: Fatal exception of type "Wikimedia\Rdbms\DBQueryError"

Exception caught inside exception handler.

Set $wgShowExceptionDetails = true; at the bottom of LocalSettings.php to show detailed debugging information.

This is while logged in.

Bryan D. says the error is "Query execution was interrupted (max_statement_time exceeded)". Lego points out that in addition to timing out, we're not serving the standard error page.


2022-03-04 23:39:40 [96eccdad-9bd1-4ea2-a1bc-771ac76f90a7] mw1411 enwiki 1.38.0-wmf.24 exception ERROR: [96eccdad-9bd1-4ea2-a1bc-771ac76f90a7] /wiki/Special:Log/MZMcBride   Wikimedia\Rdbms\DBQueryError: Error 1969: Query execution was interrupted (max_statement_time exceeded) (db1134)
Function: IndexPager::buildQueryInfo (LogPager)
Query: SET STATEMENT max_statement_time=30 FOR SELECT  /*! STRAIGHT_JOIN */ log_id,log_type,log_action,log_timestamp,log_namespace,log_title,log_params,log_deleted,user_id,user_name,user_editcount,log_actor,logging_actor.actor_user AS `log_user`,logging_actor.actor_name AS `log_user_text`,comment_log_comment.comment_text AS `log_comment_text`,comment_log_comment.comment_data AS `log_comment_data`,comment_log_comment.comment_id AS `log_comment_cid`,(SELECT  GROUP_CONCAT(ctd_name SEPARATOR ',')  FROM `change_tag` JOIN `change_tag_def` ON ((ct_tag_id=ctd_id))   WHERE ct_log_id=log_id  ) AS `ts_tags`  FROM `logging` JOIN `actor` `logging_actor` ON ((actor_id=log_actor)) LEFT JOIN `user` ON ((user_id=logging_actor.actor_user)) JOIN `comment` `comment_log_comment` ON ((comment_log_comment.comment_id = log_comment_id))   WHERE (log_type NOT IN ('spamblacklist','titleblacklist','urlshortener','abusefilter','abusefilterprivatedetails','oath','suppress')) AND (log_type != 'review') AND (log_type != 'thanks') AND (log_type != 'patrol') AND (log_type != 'tag') AND log_actor = 24276 AND ((log_deleted & 4) = 0)  ORDER BY log_timestamp DESC LIMIT 51  
 {"exception_url":"/wiki/Special:Log/MZMcBride","reqId":"96eccdad-9bd1-4ea2-a1bc-771ac76f90a7","caught_by":"entrypoint"} 
[Exception Wikimedia\Rdbms\DBQueryError] (/srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/Database.php:1655) Error 1969: Query execution was interrupted (max_statement_time exceeded) (db1134)
Function: IndexPager::buildQueryInfo (LogPager)
Query: SET STATEMENT max_statement_time=30 FOR SELECT  /*! STRAIGHT_JOIN */ log_id,log_type,log_action,log_timestamp,log_namespace,log_title,log_params,log_deleted,user_id,user_name,user_editcount,log_actor,logging_actor.actor_user AS `log_user`,logging_actor.actor_name AS `log_user_text`,comment_log_comment.comment_text AS `log_comment_text`,comment_log_comment.comment_data AS `log_comment_data`,comment_log_comment.comment_id AS `log_comment_cid`,(SELECT  GROUP_CONCAT(ctd_name SEPARATOR ',')  FROM `change_tag` JOIN `change_tag_def` ON ((ct_tag_id=ctd_id))   WHERE ct_log_id=log_id  ) AS `ts_tags`  FROM `logging` JOIN `actor` `logging_actor` ON ((actor_id=log_actor)) LEFT JOIN `user` ON ((user_id=logging_actor.actor_user)) JOIN `comment` `comment_log_comment` ON ((comment_log_comment.comment_id = log_comment_id))   WHERE (log_type NOT IN ('spamblacklist','titleblacklist','urlshortener','abusefilter','abusefilterprivatedetails','oath','suppress')) AND (log_type != 'review') AND (log_type != 'thanks') AND (log_type != 'patrol') AND (log_type != 'tag') AND log_actor = 24276 AND ((log_deleted & 4) = 0)  ORDER BY log_timestamp DESC LIMIT 51  

  #0 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/Database.php(1639): Wikimedia\Rdbms\Database->getQueryException(string, integer, string, string)
  #1 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/Database.php(1613): Wikimedia\Rdbms\Database->getQueryExceptionAndLog(string, integer, string, string)
  #2 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/Database.php(1207): Wikimedia\Rdbms\Database->reportQueryError(string, integer, string, string, boolean)
  #3 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/Database.php(1859): Wikimedia\Rdbms\Database->query(string, string, integer)
  #4 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/DBConnRef.php(69): Wikimedia\Rdbms\Database->select(array, array, array, string, array, array)
  #5 /srv/mediawiki/php-1.38.0-wmf.24/includes/libs/rdbms/database/DBConnRef.php(319): Wikimedia\Rdbms\DBConnRef->__call(string, array)
  #6 /srv/mediawiki/php-1.38.0-wmf.24/includes/pager/IndexPager.php(459): Wikimedia\Rdbms\DBConnRef->select(array, array, array, string, array, array)
  #7 /srv/mediawiki/php-1.38.0-wmf.24/includes/pager/IndexPager.php(283): IndexPager->reallyDoQuery(string, integer, boolean)
  #8 /srv/mediawiki/php-1.38.0-wmf.24/includes/logging/LogPager.php(489): IndexPager->doQuery()
  #9 /srv/mediawiki/php-1.38.0-wmf.24/includes/pager/IndexPager.php(611): LogPager->doQuery()
  #10 /srv/mediawiki/php-1.38.0-wmf.24/includes/specials/SpecialLog.php(282): IndexPager->getBody()
  #11 /srv/mediawiki/php-1.38.0-wmf.24/includes/specials/SpecialLog.php(163): SpecialLog->show(FormOptions, array)
  #12 /srv/mediawiki/php-1.38.0-wmf.24/includes/specialpage/SpecialPage.php(671): SpecialLog->execute(string)
  #13 /srv/mediawiki/php-1.38.0-wmf.24/includes/specialpage/SpecialPageFactory.php(1378): SpecialPage->run(string)
  #14 /srv/mediawiki/php-1.38.0-wmf.24/includes/MediaWiki.php(315): MediaWiki\SpecialPage\SpecialPageFactory->executePath(string, RequestContext)
  #15 /srv/mediawiki/php-1.38.0-wmf.24/includes/MediaWiki.php(910): MediaWiki->performRequest()
  #16 /srv/mediawiki/php-1.38.0-wmf.24/includes/MediaWiki.php(564): MediaWiki->main()
  #17 /srv/mediawiki/php-1.38.0-wmf.24/index.php(53): MediaWiki->run()
  #18 /srv/mediawiki/php-1.38.0-wmf.24/index.php(46): wfIndexMain()
  #19 /srv/mediawiki/w/index.php(3): require(string)
  #20 {main}

Event Timeline

Reedy changed the subtype of this task from "Bug Report" to "Production Error".Mar 4 2022, 11:41 PM
Reedy updated the task description. (Show Details)
Krinkle renamed this task from "MediaWiki internal error" when visiting https://en.wikipedia.org/wiki/Special:Log/MZMcBride to Consistent fatal timeout when visiting Special:Log default view for some users.Mar 14 2022, 4:39 PM
Krinkle edited projects, added MediaWiki-Logevents; removed MediaWiki-Special-pages.
Krinkle triaged this task as High priority.Mar 14 2022, 4:42 PM
Krinkle subscribed.

Some importants aspect to this:

  • It happens consistently for this URL.
  • It happens with the default settings, so simply clicking on "View logs" from the user page, contributions page, or elsewhere will trigger this.
  • It makes the logs inaccessible to most people. This is not a "power user" case of picking settings that perform badly. The logs simply can't be interacted with.

In case another example helps:
I just got the same thing when trying to apply the Twinkle tag to Special:Log/delete.
Testing other tags...
The tag moved with FileImporter works properly (and also has thousands of results),
The tag Huggle has very slow results (it only has 18 entries, all from 2015).

With twinkle, the error is:

MediaWiki internal error.

Original exception: [863a3b40-5d69-47f2-b2c6-46518612f243] 2022-03-16 19:15:21: Fatal exception of type "Wikimedia\Rdbms\DBQueryError"

Exception caught inside exception handler.

Set $wgShowExceptionDetails = true; at the bottom of LocalSettings.php to show detailed debugging information.

It seems like the regular error page is being rendered now, at least:

Screen Shot 2022-03-29 at 10.21.28 PM.png (2×3 px, 865 KB)

Change 777821 had a related patch set uploaded (by Func; author: Func):

[mediawiki/core@master] LogPager: Merge filter of log type into single NOT IN() clause

https://gerrit.wikimedia.org/r/777821

While that patch would make the query look nicer but the optimizer parses the query to a tree so it really doesn't make a difference in performance. Compare:

wikiadmin@10.64.16.186(enwiki)> explain SELECT  /*! STRAIGHT_JOIN */ log_id,log_type,log_action,log_timestamp,log_namespace,log_title,log_params,log_deleted,user_id,user_name,user_editcount,log_actor,logging_actor.actor_user AS `log_user`,logging_actor.actor_name AS `log_user_text`,comment_log_comment.comment_text AS `log_comment_text`,comment_log_comment.comment_data AS `log_comment_data`,comment_log_comment.comment_id AS `log_comment_cid`,(SELECT  GROUP_CONCAT(ctd_name SEPARATOR ',')  FROM `change_tag` JOIN `change_tag_def` ON ((ct_tag_id=ctd_id))   WHERE ct_log_id=log_id  ) AS `ts_tags`  FROM `logging` JOIN `actor` `logging_actor` ON ((actor_id=log_actor)) LEFT JOIN `user` ON ((user_id=logging_actor.actor_user)) JOIN `comment` `comment_log_comment` ON ((comment_log_comment.comment_id = log_comment_id))   WHERE (log_type NOT IN ('spamblacklist','titleblacklist','urlshortener','abusefilter','abusefilterprivatedetails','oath','suppress')) AND (log_type != 'review') AND (log_type != 'thanks') AND (log_type != 'patrol') AND (log_type != 'tag') AND log_actor = 24276 AND ((log_deleted & 4) = 0)  ORDER BY log_timestamp DESC LIMIT 51 ;
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
| id   | select_type        | table               | type   | possible_keys                                                    | key           | key_len | ref                             | rows | Extra       |
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
|    1 | PRIMARY            | logging             | index  | log_actor_type_time,log_type_action,log_type_time,log_actor_time | log_times     | 16      | NULL                            | 3131 | Using where |
|    1 | PRIMARY            | logging_actor       | const  | PRIMARY                                                          | PRIMARY       | 8       | const                           | 1    |             |
|    1 | PRIMARY            | user                | eq_ref | PRIMARY                                                          | PRIMARY       | 4       | enwiki.logging_actor.actor_user | 1    | Using where |
|    1 | PRIMARY            | comment_log_comment | eq_ref | PRIMARY                                                          | PRIMARY       | 8       | enwiki.logging.log_comment_id   | 1    |             |
|    2 | DEPENDENT SUBQUERY | change_tag          | ref    | ct_log_tag_id,ct_tag_id_id                                       | ct_log_tag_id | 5       | enwiki.logging.log_id           | 8    | Using index |
|    2 | DEPENDENT SUBQUERY | change_tag_def      | eq_ref | PRIMARY                                                          | PRIMARY       | 4       | enwiki.change_tag.ct_tag_id     | 1    |             |
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
6 rows in set (0.026 sec)

wikiadmin@10.64.16.186(enwiki)> explain SELECT  /*! STRAIGHT_JOIN */ log_id,log_type,log_action,log_timestamp,log_namespace,log_title,log_params,log_deleted,user_id,user_name,user_editcount,log_actor,logging_actor.actor_user AS `log_user`,logging_actor.actor_name AS `log_user_text`,comment_log_comment.comment_text AS `log_comment_text`,comment_log_comment.comment_data AS `log_comment_data`,comment_log_comment.comment_id AS `log_comment_cid`,(SELECT  GROUP_CONCAT(ctd_name SEPARATOR ',')  FROM `change_tag` JOIN `change_tag_def` ON ((ct_tag_id=ctd_id))   WHERE ct_log_id=log_id  ) AS `ts_tags`  FROM `logging` JOIN `actor` `logging_actor` ON ((actor_id=log_actor)) LEFT JOIN `user` ON ((user_id=logging_actor.actor_user)) JOIN `comment` `comment_log_comment` ON ((comment_log_comment.comment_id = log_comment_id))   WHERE (log_type NOT IN ('spamblacklist','titleblacklist','urlshortener','abusefilter','abusefilterprivatedetails','oath','suppress', 'review', 'thanks', 'patrol', 'tag')) AND log_actor = 24276 AND ((log_deleted & 4) = 0)  ORDER BY log_timestamp DESC LIMIT 51 ;
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
| id   | select_type        | table               | type   | possible_keys                                                    | key           | key_len | ref                             | rows | Extra       |
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
|    1 | PRIMARY            | logging             | index  | log_actor_type_time,log_type_action,log_type_time,log_actor_time | log_times     | 16      | NULL                            | 3131 | Using where |
|    1 | PRIMARY            | logging_actor       | const  | PRIMARY                                                          | PRIMARY       | 8       | const                           | 1    |             |
|    1 | PRIMARY            | user                | eq_ref | PRIMARY                                                          | PRIMARY       | 4       | enwiki.logging_actor.actor_user | 1    | Using where |
|    1 | PRIMARY            | comment_log_comment | eq_ref | PRIMARY                                                          | PRIMARY       | 8       | enwiki.logging.log_comment_id   | 1    |             |
|    2 | DEPENDENT SUBQUERY | change_tag          | ref    | ct_log_tag_id,ct_tag_id_id                                       | ct_log_tag_id | 5       | enwiki.logging.log_id           | 8    | Using index |
|    2 | DEPENDENT SUBQUERY | change_tag_def      | eq_ref | PRIMARY                                                          | PRIMARY       | 4       | enwiki.change_tag.ct_tag_id     | 1    |             |
+------+--------------------+---------------------+--------+------------------------------------------------------------------+---------------+---------+---------------------------------+------+-------------+
6 rows in set (0.003 sec)

The problem is that logging table in enwiki seems to have bad statistics of cardinality and distribution of the indexes and as result picking the wrong index sometimes, It is being worked on.

Existing index:

INDEX log_actor_time (log_actor, log_timestamp),
INDEX log_times (log_timestamp),
INDEX log_actor_type_time (log_actor, log_type, log_timestamp),

log_times is the worse case (except full scan), because for the actor in the where condition there is an extra index log_actor_time (which shows up in my local explain), even log_actor_type_time could be a better index, but the NOT conditions are bad for index usage. It could be better to make a positive list instead of the negative list (https://gerrit.wikimedia.org/r/c/mediawiki/core/+/258413).

When cardinality are wrong, that sounds like a DBA has to run something like ANALYZE TABLE and nothing to fix in code

Ladsgroup assigned this task to Marostegui.

Fixed now. T304626

Change 798505 had a related patch set uploaded (by Ladsgroup; author: Amir Sarabadani):

[mediawiki/core@master] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798505

Ladsgroup added a project: DBA.
Ladsgroup added a subscriber: Marostegui.

Change 798505 merged by jenkins-bot:

[mediawiki/core@master] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798505

Change 798814 had a related patch set uploaded (by Ladsgroup; author: Amir Sarabadani):

[mediawiki/core@wmf/1.39.0-wmf.13] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798814

Change 798815 had a related patch set uploaded (by Ladsgroup; author: Amir Sarabadani):

[mediawiki/core@wmf/1.39.0-wmf.12] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798815

Change 798814 merged by jenkins-bot:

[mediawiki/core@wmf/1.39.0-wmf.13] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798814

Mentioned in SAL (#wikimedia-operations) [2022-05-25T09:43:16Z] <ladsgroup@deploy1002> Synchronized php-1.39.0-wmf.13/includes/logging/LogPager.php: Backport: [[gerrit:798814|logging: Add index hint when asking for a specific user (T303089)]] (duration: 00m 49s)

Change 798815 merged by jenkins-bot:

[mediawiki/core@wmf/1.39.0-wmf.12] logging: Add index hint when asking for a specific user

https://gerrit.wikimedia.org/r/798815

Mentioned in SAL (#wikimedia-operations) [2022-05-25T10:08:06Z] <ladsgroup@deploy1002> Synchronized php-1.39.0-wmf.12/includes/logging/LogPager.php: Backport: [[gerrit:798815|logging: Add index hint when asking for a specific user (T303089)]] (duration: 00m 52s)