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I always follow most of the episodes released by Lukas Fittl as part of "5 mins of Postgres". It's great to have an episode featuring one of my blogs, which was the result of performance improvements recommended in the #PostgreSQL Slack channel. If you are a database or performance enthusiast, do check out the episode explaining the overall problems with more depth and explanation.
In this week's 5mins of #Postgres we discuss the equivalence class behavior in the Postgres planner, which allows the planner to reuse a filter condition on a single table across multiple joined tables (if they are joined on the column referenced in the filter) and how it only supports equality ("=") comparisons. Most notably, this is not supported for IN lists / ANY clauses, as described by Deepak Mahto in a recent blog post, based on a Postgres Slack discussion. We discuss the implications of this, including when you should add a WHERE clause to help the planner along - and what the community has discussed in the past to address this, and the related issue for inequality comparisons like ">=". Watch the full episode: https://lnkd.in/guQXQe_s
