Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>, Dilip Kumar <dilipbalaut@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Date: 2021-05-27T03:34:53Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> Yea, I tested that - it does help in the integer case. But the bigger
> contributors are the loop over the attributes, and especially the access
> to the datum's compression method. Particularly the latter seems hard to
> avoid.

So maybe we should just dump the promise that VACUUM FULL will recompress
everything?  I'd be in favor of that actually, because it seems 100%
outside the charter of either VACUUM FULL or CLUSTER.

			regards, tom lane

Commits

  1. Remove forced toast recompression in VACUUM FULL/CLUSTER

  2. Rethink definition of pg_attribute.attcompression.

  3. Fix memory leak when de-toasting compressed values in VACUUM FULL/CLUSTER

  4. Re-order pg_attribute columns to eliminate some padding space.

  5. Add more TAP tests for pg_dump with attribute compression