Re: performance issue with bitmap index scans on huge amounts of big jsonb documents

> big_jsonb @> '[{"x": 1, "filler": "cfcd208495d565ef66e7dff9f98764da"}]';

I wonder why bitmap heap scan adds such a big amount of time on top of the plain bitmap index scan.
It seems to me, that the recheck is active although all blocks are exact [1] and that pg is loading the jsonb for the recheck.

Is this an expected behavior?

You could try changing the type of index to jsonb_path_ops.  In your given example, it won't make a difference, because you are actually counting half the table and so half the table needs to be rechecked.  But in my example, jsonb_path_ops successfully rejects all the rows at the index stage.

Cheers,

Jeff