Horton

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

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Date: 2021-05-25T05:46:27Z
Lists: pgsql-hackers 
On Mon, May 24, 2021 at 02:46:11PM +0530, Dilip Kumar wrote:
> Like this.
>   if (TupleDescAttr(newTupDesc, i)->attisdropped)
>      isnull[i] = true;
>   else
>      tup_values[i] = values[i];

That would work.  Your suggestion, as I understood it first, makes the
code simpler by not using tup_values at all as the set of values[] is
filled when the values and nulls are extracted.  So I have gone with
this simplification, and applied the patch (moved a bit the comments
while on it).
--
Michael

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