For doing a simple equality query such as

EXPLAIN SELECT * FROM table where x = 1;

I see that a Bitmap Index scan is done using the BTree indexes. Apparently, Bitmap Index scans disable Hash indexes but I'm curious as to why? Wouldn't the query be faster if we can hash the pointer values and then run the page fetches afterwards?


Hash indexes are obsolete. Don't use them. They don't support crash safety either. Performance tests show that b-tree indexes tend to be on par with hash indexes for most purposes anyway.

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