Subject: Re: Optimize update of tables with generated columns
To: Pavel Stehule <pavel.stehule@gmail.com>
References: <b05e781a-fa16-6b52-6738-761181204567@2ndquadrant.com>
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 <CAFj8pRA417+4wrHMSXLY_D==Ca7fRd0kNHOT6DaLc906AyKiJg@mail.gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Organization: 2ndQuadrant
Message-ID: <f7f78f54-d984-da56-0df1-963cc2d2e736@2ndquadrant.com>
Date: Mon, 17 Feb 2020 16:16:40 +0100
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On 2020-02-13 16:16, Pavel Stehule wrote:
> čt 13. 2. 2020 v 14:40 odesílatel Peter Eisentraut 
> <peter.eisentraut@2ndquadrant.com 
> <mailto:peter.eisentraut@2ndquadrant.com>> napsal:
> 
>     On 2019-12-21 07:47, Peter Eisentraut wrote:
>      > When updating a table row with generated columns, we only need to
>      > recompute those generated columns whose base columns have changed in
>      > this update and keep the rest unchanged.  This can result in a
>      > significant performance benefit (easy to reproduce for example with a
>      > tsvector column).  The required information was already kept in
>      > RangeTblEntry.extraUpdatedCols; we just have to make use of it.
>      >
>      > A small problem is that right now ExecSimpleRelationUpdate() does not
>      > populate extraUpdatedCols.  That needs fixing first.
> 
>     Here is an updated patch set that contains a fix for the issue above
>     (should be backpatched IMO) and the actual performance patch as before.
> 
> 
> + 1
> 
> I tested check-world without problems, and changes of patch has sense 
> for me.

committed, thanks

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services