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by zadikian 49 days ago
Last time I almost used a hash index in Postgres, I learned it was an incomplete feature and not crash-safe yet. This was v9.3? At that same time, MySQL had them and they were ok to use.

Later that got fixed, but I haven't tried again since, just been using btree because it seemed like Postgres favored that and it has theoretical advantages too.
1 comments
daneel_w 48 days ago
They are fully stable and perform very well in Postgres today. There are some caveats, but they don't result in any sort of hiccups or unpredictable behavior.
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zadikian 47 days ago
Yeah that's what I've read too. Just haven't gotten around to trying them.

You've probably already read the Postgres docs on hash indexes, but just in case, it says "hash indexes may not be suitable for tables with rapidly increasing number of rows." I agree with the other commenter that it's worth at least trying without them if you haven't already, even though you're already VACUUMing.

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