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help / color / mirror / Atom feedFrom: Tom Lane <tgl@sss.pgh.pa.us>
To: Adrian Klaver <adrian.klaver@aklaver.com>
Cc: Tim Dudgeon <tdudgeon.ml@gmail.com>
Cc: pgsql-sql@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [SQL] querying with index on jsonb slower than standard column. Why?
Date: Mon, 08 Dec 2014 16:22:56 -0500
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Adrian Klaver <adrian.klaver@aklaver.com> writes:
> I redid the test on my 32-bit machine, setting work_mem=16MB, and I got
> comparable results to what I saw on the 64-bit machine. So, what I am
> still am puzzled by is why work_mem seems to make the two paths
> equivalent in time?:
If work_mem is large enough that we never have to go through
tbm_lossify(), then the recheck condition will never be executed,
so its speed doesn't matter.
(So the near-term workaround for Tim is to raise work_mem when
working with tables of this size.)
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, adrian.klaver@aklaver.com, tdudgeon.ml@gmail.com, pgsql-performance@postgresql.org
Subject: Re: [SQL] querying with index on jsonb slower than standard column. Why?
In-Reply-To: <4746.1418073776@sss.pgh.pa.us>
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