Avoid including unnecessary pg_locks references when counting jobs #789
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Previously, the executed query for in particular the `succeeded` scope included a join against `pg_locks`. This is not particularly useful, and unfortunately triggers evaluation of that join criterion, with noticable expense as job volume grows. This change modifies the jobs filter logic to only include those joins in the necessary locations (`running`) and when loading records for practical enumeration.
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@mkrfowler thank you! The Dashboard is very unoptimized so I appreciate the help. I want to poke at it locally for a bit, but I think it'll be good 👍 |
bensheldon
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We've been observing some performance limitations with the GoodJob dashboard. I believe this to be largely a consequence of performing live counts on an insufficiently-pruned table relative to the available database resource, but I noted that the dashboard count queries include a join against
pg_locks. In the event that there are a substantial number of e.g.succeededjobs, this actually gets quite expensive, and isn't necessary to satisfy counts.This PR is a bit of an opportunistic approach to avoid that cost.