On Fri, 2024-10-11 at 00:19 +0530, sud wrote: > I have never used any 'hash index' but saw documents in the past suggesting > issues > around hash index , like WAL doesnt generate for "hash index" which means we > can't > get the hash index back after crash also they are not applied to replicas etc. > And also these indexes can not be used for range queries , for sorting etc. > > However, we are seeing that one of the databases has multiple hash indexes > created. > So I wanted to understand from experts here, if it's advisable in any specific > scenarios over B-tre despite such downsides? > Note- Its version 15.4 database.
It is safe to use them, but in my tests I didn't find a realistic case where the were better than a B-tree index: https://www.cybertec-postgresql.com/en/postgresql-hash-index-performance/ Keep them if they do the trick for you, but I'd use B-tree indexes instead. Yours, Laurenz Albe
