Index bloat in Postgres can cause problems, but it’s easy to miss.
I’ve written about how vacuum problems can prevent PostgreSQL from using covering indexes, and index bloat is one of the things that can make vacuum struggle.
Here’s what you need to know about index bloat, how to find it, and how to fix it.
Dear Postgres, Why won’t you use my covering index?
Lately I’ve been learning to tune queries running against PostgreSQL, and it’s pretty delightful. One fun question that I worked through struck me something that most Postgres users probably encounter one way or another: sometimes you may create the perfect index that covers a given query, but the query planner will choose to ignore it and scan the base table.
Why in the world would it do that?
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