Re: Move pg_attribute.attcompression to earlier in struct for reduced size?

Hi,

On 2021-05-26 20:35:46 -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?

Oh, it'll definitely be more expensive in that case - but that seems
fair game. What I was wondering about was whether VACUUM FULL would be
measurably slower, because we'll now call toast_get_compression_id() on
each varlena datum. It's pretty easy for VACUUM FULL to be CPU bound
already, and presumably this'll add a bit.

Greetings,

Andres Freund