Before we deploy new Updater service into production, we want to test it thoroughly, since problems in the updater would lead to wrong data queried and ultimately desynchronization between Wikidata and WDQS bases.
The current test plan is as follows:
- Deploy a logger config change to enable UPDATED_ENTITY_IDS: https://gerrit.wikimedia.org/r/c/operations/puppet/+/551549
- Deploy new updater code in production but not enable it (this is to ensure we didn't break anything on the way, and that we're running on the same codebase)
- Stop the updater on two servers and copy the journal from one to another (wdqs1006 -> wdqs1004)
- Configure wdqs1004 to use the new updater: https://gerrit.wikimedia.org/r/c/operations/puppet/+/551169
- Start the updater on both server
- Collect some metrics about times and lag (make sure T238408 is fixed before starting the test)
- Stop the updater on both server
- pick a samples of updated entityIds and extract their data using the new debugging endpoint on both wdqs1004 and wdqs1006 (https://gerrit.wikimedia.org/r/c/wikidata/query/rdf/+/551505)
- re-enable the updater on both servers
- compare the results
note: At this point wdqs1004 should still be running the merging updater.
After all these tests has been run and returned satisfactory results, we can start enabling new updater option on production hosts.