TLDR: Wiki Replicas' architecture is being redesigned for stability and
performance. Cross database JOINs will not be available and a host
connection will only allow querying its associated DB. See [1]
<https://wikitech.wikimedia.org/wiki/News/Wiki_Replicas_2020_Redesign> for
more details.
Hi!
In the interest of making and keeping Wiki Replicas a stable and performant
service, a new backend architecture is needed. There is some impact in the
features and usage patterns.
What should I do? To avoid breaking changes, you can start making the
following changes *now*:
- Update existing tools to ensure queries are executed against the proper
database connection
- Eg: If you want to query the `eswiki_p` DB, you must connect to the
`eswiki.analytics.db.svc.eqiad.wmflabs` host and `eswiki_p` DB, and not to
enwiki or other hosts
- Check your existing tools and services queries for cross database JOINs,
rewrite the joins in application code
- Eg: If you are doing a join across databases, for example joining
`enwiki_p` and `eswiki_p`, you will need to query them separately, and
filter the results of the separate queries in the code
Timeline:
- November - December: Early adopter testing
- January 2021: Existing and new systems online, transition period starts
- February 2021: Old hardware is decommissioned
We need your help
- If you would like to beta test the new architecture, please let us know
and we will reach out to you soon
- Sharing examples / descriptions of how a tool or service was updated,
writing a common solution or some example code others can utilize and
reference, helping others on IRC and the mailing lists
If you have questions or need help adapting your code or queries, please
contact us [2]
<https://wikitech.wikimedia.org/wiki/Help:Cloud_Services_communication>, or
write on the talk page [3]
<https://wikitech.wikimedia.org/wiki/Talk:News/Wiki_Replicas_2020_Redesign>.
We will be sending reminders, and more specific examples of the changes via
email and on the wiki page. For more information see [1]
<https://wikitech.wikimedia.org/wiki/News/Wiki_Replicas_2020_Redesign>.
[1]:
https://wikitech.wikimedia.org/wiki/News/Wiki_Replicas_2020_Redesign
[2]:
https://wikitech.wikimedia.org/wiki/Help:Cloud_Services_communication
[3]:
https://wikitech.wikimedia.org/wiki/Talk:News/Wiki_Replicas_2020_Redesign
--
Joaquin Oltra Hernandez
Developer Advocate - Wikimedia Foundation