system-config

Commit Graph

Author	SHA1	Message	Date
Ian Wienand	570ca85cd8	gerrit: add mariadb_container option This adds a local mariadb container to the gerrit host to hold the accountPatchReviewDb database. This is inspired by a few things - since migration to NoteDB, there is only one table left where Gerrit records what files have been reviewed for a change. This logically scales with the number of reviews users are doing. Pulling the stats on this, we can see since the NoteDB upgrade this went from a very busy database (~300 queries/70 commits per second) to barely registering one hit per second : https://imgur.com/a/QGJV7Fw Thus separating the db to an external host for performance reasons is not a large concern any more. - emperically we've done a bad job in keeping the existing hosted db up-to-date; it's still running mysql 5.1 and we have been hit by bugs such as the one referenced in-line which silently drops backups. - The other gerrit option is to use an on-disk H2 database. This is certainly an option, however you need special tools to interact with it for migration, etc. and it's not safe to backup from files on disk (as opposed to mysqldump). Upstream advice is unclear, and varies between H2 being a performance bottleneck to this being ephemeral data that users don't care about. We know how to admin mariadb/mysql and this allows us to migrate and backup data, so seems like the best choice. - we have a pressing need to update the server to a new operating system. Running the db alongside the gerrit instance minimises fiddling we have to do manging connections to and migrating the hosted db systems. - related to that, we are tending towards more provider independence for control-plane servers. A hosted database product is not always provided, so this gives us more flexibility in moving things around. - the main concern here is memory usage. "docker stats" reports a quiescent container, freshly started on a 8GB host: gerrit-compose_mariadb_1 67.32MiB After loading a copy of the production table, and then dumping it back to a file the same container reports: gerrit-compose_mariadb_1 462.6MiB The existing remote mysql configuration path remains mostly the same. We move the gerrit startup into a script rather than a CMD so we can call it after a "wait for db" script in the mariadb_container case (this is the reccommeded way to enforce ordering [1]). Backups of the local container need different dump commands; backups are relocated to a new file and updated. Testing is converted to use this rather than a local H2 database. [1] https://docs.docker.com/compose/startup-order/ Change-Id: Iec981ef3c2e38889f91e9759e66295dbfb499c2e	2 years ago

Author

SHA1

Message

Date

Ian Wienand

570ca85cd8

gerrit: add mariadb_container option

This adds a local mariadb container to the gerrit host to hold the
accountPatchReviewDb database.  This is inspired by a few things

 - since migration to NoteDB, there is only one table left where
   Gerrit records what files have been reviewed for a change.  This
   logically scales with the number of reviews users are doing.
   Pulling the stats on this, we can see since the NoteDB upgrade this
   went from a very busy database (~300 queries/70 commits per second)
   to barely registering one hit per second :
   https://imgur.com/a/QGJV7Fw

   Thus separating the db to an external host for performance reasons
   is not a large concern any more.

 - emperically we've done a bad job in keeping the existing hosted db
   up-to-date; it's still running mysql 5.1 and we have been hit by
   bugs such as the one referenced in-line which silently drops
   backups.

 - The other gerrit option is to use an on-disk H2 database.  This is
   certainly an option, however you need special tools to interact
   with it for migration, etc. and it's not safe to backup from files
   on disk (as opposed to mysqldump).  Upstream advice is unclear, and
   varies between H2 being a performance bottleneck to this being
   ephemeral data that users don't care about.  We know how to admin
   mariadb/mysql and this allows us to migrate and backup data, so
   seems like the best choice.

 - we have a pressing need to update the server to a new operating
   system.  Running the db alongside the gerrit instance minimises
   fiddling we have to do manging connections to and migrating the
   hosted db systems.

 - related to that, we are tending towards more provider independence
   for control-plane servers.  A hosted database product is not always
   provided, so this gives us more flexibility in moving things
   around.

 - the main concern here is memory usage.  "docker stats" reports a
   quiescent container, freshly started on a 8GB host:

    gerrit-compose_mariadb_1  67.32MiB

   After loading a copy of the production table, and then dumping it
   back to a file the same container reports:

    gerrit-compose_mariadb_1  462.6MiB

The existing remote mysql configuration path remains mostly the same.
We move the gerrit startup into a script rather than a CMD so we can
call it after a "wait for db" script in the mariadb_container case
(this is the reccommeded way to enforce ordering [1]).

Backups of the local container need different dump commands; backups
are relocated to a new file and updated.

Testing is converted to use this rather than a local H2 database.

[1] https://docs.docker.com/compose/startup-order/

Change-Id: Iec981ef3c2e38889f91e9759e66295dbfb499c2e

1 Commits (master)