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help / color / mirror / Atom feedFrom: Peter Geoghegan <[email protected]>
To: Tom Lane <[email protected]>
Cc: [email protected]
Subject: Re: default opclass for jsonb (was Re: Call for GIST/GIN/SP-GIST opclass documentation)
Date: Tue, 8 Apr 2014 14:57:44 -0700
Message-ID: <CAM3SWZQzOxmryVe_bdu9WhqbJTBoiqM7knvKm0oRYxvfsFnz7Q@mail.gmail.com> (raw)
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On Tue, Apr 8, 2014 at 2:46 PM, Tom Lane <[email protected]> wrote:
> Well, let me see if I understand the situation correctly:
>
> * jsonb_ops supports more operators
>
> * jsonb_hash_ops produces smaller, better-performing indexes
>
> * jsonb_ops falls over on inputs with wide field values, but
> jsonb_hash_ops does not
There might be some compelling cases for indexing existence rather
than containment, since the recheck flag isn't set there, but in
general this summary seems sound. I would say that broadly, existence
is a less useful operator than containment, and so jsonb_hash_ops is
broadly more compelling. I didn't propose changing the default due to
concerns about the POLA, but I'm happy to be told that those concerns
were out of proportion to the practical benefits of a different
default.
--
Peter Geoghegan
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To: [email protected]
Cc: [email protected], [email protected], [email protected]
Subject: Re: default opclass for jsonb (was Re: Call for GIST/GIN/SP-GIST opclass documentation)
In-Reply-To: <CAM3SWZQzOxmryVe_bdu9WhqbJTBoiqM7knvKm0oRYxvfsFnz7Q@mail.gmail.com>
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