Re: Anyone know any WP which explains about FTS vs Index Scan?

From: Chris Stephens <>
Date: Tue, 10 Apr 2018 19:55:32 +0000
Message-ID: <>

"Using an index is plain stupid if the filter is highly selective" .. that's not necessarily true. sorting and aggregation can be supported by appropriate indexes.

On Tue, Apr 10, 2018 at 11:40 AM Andy Sayer <> wrote:

> Flip the problem on its head. Where does it say in the docs that full
> table scans must be reduced?
> Obviously, full table scans are powerful and are the best way of getting
> lots of data quickly if your filters are highly selective (return many
> rows).
> Using an index is plain stupid if the filter is highly selective, it is
> crazy to want to visit many blocks one by one, using a fresh buffer in the
> cache as you go.
> If your dinasaur doesn’t agree that something that is faster and uses less
> latches is better then maybe they’re really an osterich?
> Or maybe they’re working to achieve a different set of metrics?
> Regards,
> Andrew

Received on Tue Apr 10 2018 - 21:55:32 CEST

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