Re: Move pg_attribute.attcompression to earlier in struct for reduced size? - Mailing list pgsql-hackers

From Michael Paquier
Subject Re: Move pg_attribute.attcompression to earlier in struct for reduced size?
Date
Msg-id YK7vIBv+DDaQuebf@paquier.xyz
Whole thread Raw
In response to Re: Move pg_attribute.attcompression to earlier in struct for reduced size?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Wed, May 26, 2021 at 08:35:46PM -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > The efficiency bit is probably going to be swamped by the addition of
> > the compression handling, given the amount of additional work we're now
> > doing in in reform_and_rewrite_tuple().
>
> Only if the user has explicitly requested a change of compression, no?

Andres' point is that we'd still initialize and run through
values_free at the end of reform_and_rewrite_tuple() for each tuple
even if there no need to do so.  Well, we could control the
initialization and the free() checks at the end of the routine if we
know that there has been at least one detoasted value, at the expense
of making the code a bit less clear, of course.
--
Michael

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