Hi @Ladsgroup :) Thanks for caring !
You'll find some minimal doc here: https://wikitech.wikimedia.org/wiki/Analytics/Systems/Cluster/Edit_data_loading with a link to the code.
Please ping in IRC or slack if you wish more details.

Changed the task from being a weird mix of requesing an application of a schema change on production and a task where the updating is coordinated. Requesting the application of a schema to production can be done in a subtask when we are at that point.

I also dropped the cuc_logid proposal, because it is quite unrelated. It is already covered by T253796.

I am going to work on a patch doing this. The other patch is more than two years old and somewhat outdated.

Change 769824 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Add actor and comment columns to CheckUser tables

https://gerrit.wikimedia.org/r/769824

Thank you for doing this!

Change 769824 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Add actor and comment columns to cu_changes

https://gerrit.wikimedia.org/r/769824

As I understand, the patch just adds the columns but is there now a plan to migrate the data? We (data engineering) would like to be kept in the loop as closely as possible here.

In T233004#7796847, @Milimetric wrote:

As I understand, the patch just adds the columns but is there now a plan to migrate the data? We (data engineering) would like to be kept in the loop as closely as possible here.

There is a plan, but no code yet. Any actual migration is currently stalled on T303603.

Change 773650 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] WIP: Add actor migration code

https://gerrit.wikimedia.org/r/773650

Change 775336 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Add actor migration code for SCHEMA_COMPAT_WRITE_BOTH

https://gerrit.wikimedia.org/r/775336

Change 537256 abandoned by Zabe:

[mediawiki/extensions/CheckUser@master] Schema change: Add columns cuc_log_id and ActorMigrate, CommentStore related

Reason:

https://gerrit.wikimedia.org/r/537256

Change 775336 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Add actor migration code for SCHEMA_COMPAT_WRITE_BOTH

https://gerrit.wikimedia.org/r/775336

Change 776224 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Use ActorStore to fetch actor id

https://gerrit.wikimedia.org/r/776224

Change 776224 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Use ActorStore to fetch actor id

https://gerrit.wikimedia.org/r/776224

Change 776249 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Add population script for cuc_actor

https://gerrit.wikimedia.org/r/776249

Change 776250 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Pin CheckUser actor migration to old schema

https://gerrit.wikimedia.org/r/776250

Change 776252 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Change actor migration to write both

https://gerrit.wikimedia.org/r/776252

Change 776250 merged by jenkins-bot:

[operations/mediawiki-config@master] Pin CheckUser actor migration to old schema

https://gerrit.wikimedia.org/r/776250

Mentioned in SAL (#wikimedia-operations) [2022-04-05T13:17:02Z] <taavi@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:776250|Pin CheckUser actor migration to old schema (T233004)]] (duration: 00m 54s)

Change 776252 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Change actor migration to write both

https://gerrit.wikimedia.org/r/776252

Change 776249 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Add population script for cuc_actor

https://gerrit.wikimedia.org/r/776249

Change 779078 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Start writing to cuc_actor in guwwiki and shnwikivoyage

https://gerrit.wikimedia.org/r/779078

Change 779078 merged by jenkins-bot:

[operations/mediawiki-config@master] Start writing to cuc_actor in guwwiki and shnwikivoyage

https://gerrit.wikimedia.org/r/779078

Mentioned in SAL (#wikimedia-operations) [2022-04-11T20:24:40Z] <urbanecm@deploy1002> Synchronized wmf-config/InitialiseSettings.php: 17c8c17: Start writing to cuc_actor in guwwiki and shnwikivoyage (T233004) (duration: 00m 51s)

Change 779912 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Acquire fresh actor id for anons

https://gerrit.wikimedia.org/r/779912

Change 779922 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Revert "Revert "Start writing to cuc_actor in guwwiki and shnwikivoyage""

https://gerrit.wikimedia.org/r/779922

Change 779912 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Acquire fresh actor id for anons

https://gerrit.wikimedia.org/r/779912

Change 782195 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] SpecialCheckUser: add support for actor migration read new

https://gerrit.wikimedia.org/r/782195

Change 779922 merged by jenkins-bot:

[operations/mediawiki-config@master] Revert "Revert "Start writing to cuc_actor in guwwiki and shnwikivoyage""

https://gerrit.wikimedia.org/r/779922

Mentioned in SAL (#wikimedia-operations) [2022-05-02T20:30:36Z] <catrope@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:779922|Revert "Revert "Start writing to cuc_actor in guwwiki and shnwikivoyage"" (T233004)]] (duration: 00m 47s)

Change 797294 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Start writing to cuc_actor in s3 and labtestwiki

https://gerrit.wikimedia.org/r/797294

Change 797312 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Start writing to cuc_actor in test wikis

https://gerrit.wikimedia.org/r/797312

Change 797312 merged by jenkins-bot:

[operations/mediawiki-config@master] Start writing to cuc_actor in test wikis

https://gerrit.wikimedia.org/r/797312

Mentioned in SAL (#wikimedia-operations) [2022-05-23T20:21:17Z] <cjming@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:797312|Start writing to cuc_actor in test wikis (T233004)]] (duration: 00m 50s)

Change 797294 merged by jenkins-bot:

[operations/mediawiki-config@master] Start writing to cuc_actor in s3, kcgwiki and labtestwiki

https://gerrit.wikimedia.org/r/797294

Mentioned in SAL (#wikimedia-operations) [2022-05-24T21:06:18Z] <cjming@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:797294|Start writing to cuc_actor in s3, kcgwiki and labtestwiki (T233004)]] (duration: 00m 52s)

Change 798993 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Acquire fresh actor id

https://gerrit.wikimedia.org/r/798993

Change 798813 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki"

https://gerrit.wikimedia.org/r/798813

Change 798813 merged by jenkins-bot:

[operations/mediawiki-config@master] Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki"

https://gerrit.wikimedia.org/r/798813

Mentioned in SAL (#wikimedia-operations) [2022-05-24T22:02:14Z] <cjming@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:798813|Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki" (T233004 T309148)]] (duration: 00m 49s)

Change 798993 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Acquire fresh actor id

https://gerrit.wikimedia.org/r/798993

Change 798817 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@wmf/1.39.0-wmf.12] Acquire fresh actor id

https://gerrit.wikimedia.org/r/798817

Change 798818 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@wmf/1.39.0-wmf.13] Acquire fresh actor id

https://gerrit.wikimedia.org/r/798818

Change 800190 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Revert "Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki""

https://gerrit.wikimedia.org/r/800190

Change 798818 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@wmf/1.39.0-wmf.13] Acquire fresh actor id

https://gerrit.wikimedia.org/r/798818

Change 800190 merged by jenkins-bot:

[operations/mediawiki-config@master] Revert "Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki""

https://gerrit.wikimedia.org/r/800190

Mentioned in SAL (#wikimedia-operations) [2022-05-26T20:53:39Z] <brennen@deploy1002> Synchronized php-1.39.0-wmf.13/extensions/CheckUser/src/Hooks.php: Backport: [[gerrit:798818|Acquire fresh actor id (T233004 T309148)]] (duration: 00m 51s)

Mentioned in SAL (#wikimedia-operations) [2022-05-26T20:55:05Z] <brennen@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:800190|Revert "Revert "Start writing to cuc_actor in s3, kcgwiki and labtestwiki"" (T233004)]] (duration: 00m 50s)

Change 800278 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Start writing to cuc_actor everywhere except s4 and s8

https://gerrit.wikimedia.org/r/800278

Change 798817 abandoned by Zabe:

[mediawiki/extensions/CheckUser@wmf/1.39.0-wmf.12] Acquire fresh actor id

Reason:

https://gerrit.wikimedia.org/r/798817

@Zabe On my local machine, running php maintenance/update.php:

Wikimedia\Rdbms\DBQueryError from line 1750 of /var/www/html/w/includes/libs/rdbms/database/Database.php: Error 1: no such column: cuc_actor
Function: MediaWiki\CheckUser\Maintenance\PopulateCucActor::doDBUpdates
Query: SELECT  cuc_id,cuc_user_text  FROM cu_changes    WHERE cuc_actor = 0 AND (cuc_id BETWEEN 5908 AND 6108)  

#0 /var/www/html/w/includes/libs/rdbms/database/Database.php(1734): Wikimedia\Rdbms\Database->getQueryException('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...')
#1 /var/www/html/w/includes/libs/rdbms/database/Database.php(1708): Wikimedia\Rdbms\Database->getQueryExceptionAndLog('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...')
#2 /var/www/html/w/includes/libs/rdbms/database/Database.php(1209): Wikimedia\Rdbms\Database->reportQueryError('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...', false)
#3 /var/www/html/w/includes/libs/rdbms/database/Database.php(1954): Wikimedia\Rdbms\Database->query('SELECT  cuc_id,...', 'MediaWiki\\Check...', 32)
#4 /var/www/html/w/includes/libs/rdbms/database/DBConnRef.php(68): Wikimedia\Rdbms\Database->select('cu_changes', Array, Array, 'MediaWiki\\Check...')
#5 /var/www/html/w/includes/libs/rdbms/database/DBConnRef.php(277): Wikimedia\Rdbms\DBConnRef->__call('select', Array)
#6 /var/www/html/w/extensions/CheckUser/maintenance/populateCucActor.php(101): Wikimedia\Rdbms\DBConnRef->select('cu_changes', Array, Array, 'MediaWiki\\Check...')
#7 /var/www/html/w/maintenance/includes/LoggedUpdateMaintenance.php(45): MediaWiki\CheckUser\Maintenance\PopulateCucActor->doDBUpdates()
#8 /var/www/html/w/maintenance/update.php(205): LoggedUpdateMaintenance->execute()
#9 /var/www/html/w/maintenance/includes/MaintenanceRunner.php(195): UpdateMediaWiki->execute()
#10 /var/www/html/w/maintenance/doMaintenance.php(85): MediaWiki\Maintenance\MaintenanceRunner->run()
#11 /var/www/html/w/maintenance/update.php(264): require_once('/var/www/html/w...')
#12 {main}

(I also ran it with --force but got the same error.)

CheckUser version 2.5 (e924e27) 06:20, 1 June 2022.

Change 773650 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Add CheckUserActorMigration service

https://gerrit.wikimedia.org/r/773650

Change 800278 merged by jenkins-bot:

[operations/mediawiki-config@master] Start writing to cuc_actor everywhere except s4 and s8

https://gerrit.wikimedia.org/r/800278

Mentioned in SAL (#wikimedia-operations) [2022-06-01T20:26:32Z] <cjming@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Config: [[gerrit:800278|Start writing to cuc_actor everywhere except s4 and s8 (T233004)]] (duration: 03m 01s)

Change 802115 had a related patch set uploaded (by Urbanecm; author: Urbanecm):

[operations/mediawiki-config@master] Revert "Start writing to cuc_actor everywhere except s4 and s8"

https://gerrit.wikimedia.org/r/802115

Change 802115 merged by Urbanecm:

[operations/mediawiki-config@master] Revert "Start writing to cuc_actor everywhere except s4 and s8"

https://gerrit.wikimedia.org/r/802115

Mentioned in SAL (#wikimedia-operations) [2022-06-01T20:58:35Z] <urbanecm@deploy1002> Synchronized wmf-config/InitialiseSettings.php: 5a8e7586bcb0933c96e8294e389c31270edb134e: Revert "Start writing to cuc_actor everywhere except s4 and s8" (T233004) (duration: 00m 32s)

In T233004#7972925, @dom_walden wrote:

@Zabe On my local machine, running php maintenance/update.php:

Wikimedia\Rdbms\DBQueryError from line 1750 of /var/www/html/w/includes/libs/rdbms/database/Database.php: Error 1: no such column: cuc_actor
Function: MediaWiki\CheckUser\Maintenance\PopulateCucActor::doDBUpdates
Query: SELECT  cuc_id,cuc_user_text  FROM cu_changes    WHERE cuc_actor = 0 AND (cuc_id BETWEEN 5908 AND 6108)  

#0 /var/www/html/w/includes/libs/rdbms/database/Database.php(1734): Wikimedia\Rdbms\Database->getQueryException('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...')
#1 /var/www/html/w/includes/libs/rdbms/database/Database.php(1708): Wikimedia\Rdbms\Database->getQueryExceptionAndLog('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...')
#2 /var/www/html/w/includes/libs/rdbms/database/Database.php(1209): Wikimedia\Rdbms\Database->reportQueryError('no such column:...', 1, 'SELECT  cuc_id,...', 'MediaWiki\\Check...', false)
#3 /var/www/html/w/includes/libs/rdbms/database/Database.php(1954): Wikimedia\Rdbms\Database->query('SELECT  cuc_id,...', 'MediaWiki\\Check...', 32)
#4 /var/www/html/w/includes/libs/rdbms/database/DBConnRef.php(68): Wikimedia\Rdbms\Database->select('cu_changes', Array, Array, 'MediaWiki\\Check...')
#5 /var/www/html/w/includes/libs/rdbms/database/DBConnRef.php(277): Wikimedia\Rdbms\DBConnRef->__call('select', Array)
#6 /var/www/html/w/extensions/CheckUser/maintenance/populateCucActor.php(101): Wikimedia\Rdbms\DBConnRef->select('cu_changes', Array, Array, 'MediaWiki\\Check...')
#7 /var/www/html/w/maintenance/includes/LoggedUpdateMaintenance.php(45): MediaWiki\CheckUser\Maintenance\PopulateCucActor->doDBUpdates()
#8 /var/www/html/w/maintenance/update.php(205): LoggedUpdateMaintenance->execute()
#9 /var/www/html/w/maintenance/includes/MaintenanceRunner.php(195): UpdateMediaWiki->execute()
#10 /var/www/html/w/maintenance/doMaintenance.php(85): MediaWiki\Maintenance\MaintenanceRunner->run()
#11 /var/www/html/w/maintenance/update.php(264): require_once('/var/www/html/w...')
#12 {main}

(I also ran it with --force but got the same error.)

CheckUser version 2.5 (e924e27) 06:20, 1 June 2022.

Huh, I can't reproduce and I also don't understand why it is happening. Which RDBMS are you using?

Change 802637 had a related patch set uploaded (by Zabe; author: Zabe):

[operations/mediawiki-config@master] Stop writing to cuc_actor on all wikis

https://gerrit.wikimedia.org/r/802637

Change 802637 merged by jenkins-bot:

[operations/mediawiki-config@master] Stop writing to cuc_actor on all wikis

https://gerrit.wikimedia.org/r/802637

Mentioned in SAL (#wikimedia-operations) [2022-06-02T21:25:57Z] <jforrester@deploy1002> Synchronized wmf-config/InitialiseSettings.php: Emergency deploy: [[gerrit:802637|Stop writing to cuc_actor on all wikis (T233004 T309737)]] (duration: 03m 15s)

In T233004#7975137, @Zabe wrote:

In T233004#7972925, @dom_walden wrote:

@Zabe On my local machine, running php maintenance/update.php:
...

Huh, I can't reproduce and I also don't understand why it is happening. Which RDBMS are you using?

sqlite3, using docker.

In T233004#7981926, @dom_walden wrote:

In T233004#7975137, @Zabe wrote:

In T233004#7972925, @dom_walden wrote:

@Zabe On my local machine, running php maintenance/update.php:
...

Huh, I can't reproduce and I also don't understand why it is happening. Which RDBMS are you using?

sqlite3, using docker.

Yeah, the schema file for sqlite is missing, I will add it.

Change 804482 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/CheckUser@master] Add cuc_actor and cuc_comment_id in sqlite aswell

https://gerrit.wikimedia.org/r/804482

Change 804482 merged by jenkins-bot:

[mediawiki/extensions/CheckUser@master] Add cuc_actor and cuc_comment_id in sqlite aswell

https://gerrit.wikimedia.org/r/804482