Hi all,

I'm writing to the list in the hope of receiving some feedback, questions, maybe answers to help us solve a conundrum with sessions we have on our Wikibase/Mediawiki installation.

We're running two different docker-based wikibase installations (one staging, one production) on two separate virtual machines. Both use the SimpleSaml extension to connect to a SAML implementation, but we have found that the random session deletion happens both with and without the SAML extension used.

The symptoms that we've seen are that out of the blue, users are disconnected from mediawiki. Since we use SAML, it's enough to click the Login link to again be connected.

The duration or number of requests until a session is deleted seems random. It does appear though, that the more (or more frequent) requests are made (and thus background jobs run) the quicker a session is deleted.

We have even tried setting $wgObjectCacheSessionExpiry = 7200; in order to exclude any TimeZone related issues which was our first suspicion. However, changing this from the default 1h session expiry does not change the behavior we're seeing.

Sessions are deleted regardless of their nature. E.g. sessions established for oauth connections are deleted in the same way and at the same time as other sessions. E.g. using wikidataintegrator we're able to run a number of requests until the CSRF token expires (with the number of requests that succeed before this happens being random):

[…]
Created Item Q379 from Class http://www.cidoc-crm.org/cidoc-crm/E34_Inscription.
Created Item Q380 from Class http://www.cidoc-crm.org/cidoc-crm/E53_Place.
Error while writing to Wikidata
ERROR creating class reference for http://www.cidoc-crm.org/cidoc-crm/E35_Title: {'error': {'code': 'badtoken', 'info': 'Invalid CSRF token.', '*': 'See https://saf-dev.bnl.lu/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes.'}}
Error while writing to Wikidata
ERROR creating object property reference for http://www.cidoc-crm.org/cidoc-crm/P16_used_specific_object: {'error': {'code': 'badtoken', 'info': 'Invalid CSRF token.', '*': 'See https://saf-dev.bnl.lu/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes.'}}

If sessions are not randomly deleted, then session renewal seems to work as planned with them being renewed after half their expiry time:

[DBQuery] SqlBagOStuff::fetchBlobMulti [0s] db.svc:3306: SELECT  keyname,value,exptime  FROM `objectcache`    WHE
RE keyname = 'mediawiki:MWSession:n9krnsfa303qk9c2osp6c81tp1k2bp5b'
[session] SessionBackend "require/require_once/MediaWiki\Session\Session->renew/MediaWiki\Session\SessionBackend-
>renew" metadata dirty for renew(): require/require_once/MediaWiki\Session\Session->renew/MediaWiki\Session\Sessi
onBackend->renew
[session] SessionBackend "n9krnsfa303qk9c2osp6c81tp1k2bp5b" force-persist for renew(): require/require_once/Media
Wiki\Session\Session->renew/MediaWiki\Session\SessionBackend->renew
[session] SessionBackend "n9krnsfa303qk9c2osp6c81tp1k2bp5b" save: dataDirty=0 metaDirty=1 forcePersist=1
[cookie] setcookie: "mediawiki_session", "n9krnsfa303qk9c2osp6c81tp1k2bp5b", "0", "/", "", "1", "1", ""
[cookie] setcookie: "mediawikiUserID", "13", "1648233666", "/", "", "1", "1", ""
[cookie] setcookie: "mediawikiUserName", "Ibl676", "1648233666", "/", "", "1", "1", ""
[cookie] already deleted setcookie: "mediawikiToken", "", "1614105666", "/", "", "1", "1", ""
[cookie] already deleted setcookie: "forceHTTPS", "", "1614105666", "/", "", "", "1", ""
[session] SessionBackend "n9krnsfa303qk9c2osp6c81tp1k2bp5b" Taking over PHP session
[session] SessionBackend "n9krnsfa303qk9c2osp6c81tp1k2bp5b" save: dataDirty=0 metaDirty=1 forcePersist=1
[cookie] already set setcookie: "mediawiki_session", "n9krnsfa303qk9c2osp6c81tp1k2bp5b", "0", "/", "", "1", "1",
""
[cookie] already set setcookie: "mediawikiUserID", "13", "1648233666", "/", "", "1", "1", ""
[cookie] already set setcookie: "mediawikiUserName", "Ibl676", "1648233666", "/", "", "1", "1", ""
[cookie] already deleted setcookie: "mediawikiToken", "", "1614105666", "/", "", "1", "1", ""
[cookie] already deleted setcookie: "forceHTTPS", "", "1614105666", "/", "", "", "1", ""
[DBQuery] SqlBagOStuff::updateTable [0.002s] db.svc:3306: REPLACE INTO `objectcache` (keyname,value,exptime) VALU
ES ('mediawiki:MWSession:n9krnsfa303qk9c2osp6c81tp1k2bp5b','...\0','20220223194106')

Here is one example where the session got deleted by whatever feels responsible to do so:

MariaDB [mediawiki]> select keyname, exptime from objectcache where keyname like 'mediawiki:MWSession%';
+------------------------------------------------------+---------------------+
| keyname                                              | exptime             |
+------------------------------------------------------+---------------------+
| mediawiki:MWSession:t7d5lms2nrma6k627c6usrgc6289en3a | 2022-03-24 17:34:34 |
+------------------------------------------------------+---------------------+
1 row in set (0.001 sec)

MariaDB [mediawiki]> select keyname, exptime from objectcache where keyname like 'mediawiki:MWSession%';
Empty set (0.001 sec)

MariaDB [mediawiki]> select now();
+---------------------+
| now()               |
+---------------------+
| 2022-03-24 17:37:15 |
+---------------------+
1 row in set (0.024 sec)

The only instance of me finding something remotely related to randomly deleting a session would be these log entries:

2022-03-24 17:03:29 51290acae35a mediawiki: SessionManager using store SqlBagOStuff                                                                                                                                                
2022-03-24 17:03:29 51290acae35a mediawiki: Saving all sessions on shutdown                                                                                                                                                        
2022-03-24 17:03:29 51290acae35a mediawiki: SessionManager using store SqlBagOStuff                                                                                                                                                
2022-03-24 17:03:29 51290acae35a mediawiki: Session "[30]MediaWiki\Session\CookieSessionProvider<-:13:Ibl676>8favvi92d08njut82j66un60r601titn": Unverified user provided and no metadata to auth it
2022-03-24 17:03:29 51290acae35a mediawiki: setcookie: "mediawiki_session", "", "1616605409", "/", "", "1", "1", ""                                                                                                                
2022-03-24 17:03:29 51290acae35a mediawiki: setcookie: "mediawikiUserID", "", "1616605409", "/", "", "1", "1", ""                                                                                                                  
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "mediawikiToken", "", "1616605409", "/", "", "1", "1", ""                                                                                                   
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "forceHTTPS", "", "1616605409", "/", "", "", "1", ""           
2022-03-24 17:03:29 51290acae35a mediawiki: SessionBackend "ujf6rcheseb51lpaojrqggb4c23s1flr" is unsaved, marking dirty in constructor    
2022-03-24 17:03:29 51290acae35a mediawiki: SessionBackend "ujf6rcheseb51lpaojrqggb4c23s1flr" save: dataDirty=1 metaDirty=1 forcePersist=0
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "mediawiki_session", "", "1616605409", "/", "", "1", "1", ""
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "mediawikiUserID", "", "1616605409", "/", "", "1", "1", ""
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "mediawikiToken", "", "1616605409", "/", "", "1", "1", ""
2022-03-24 17:03:29 51290acae35a mediawiki: already deleted setcookie: "forceHTTPS", "", "1616605409", "/", "", "", "1", ""                                                                                                        
2022-03-24 17:03:29 51290acae35a mediawiki: Saving all sessions on shutdown   

IBL676 is my SAML ID. I'm not sure why the user is unverified and what metadata would be used/required to verify it?

Looking forward to any advice on how to further investigate what is going on here.

Regards,
David