Re: [PoC] Improve dead tuple storage for lazy vacuum

On Thu, Mar 28, 2024 at 12:55 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> I think the patch is in good shape. Do you have other comments or
> suggestions, John?

--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1918,11 +1918,6 @@ include_dir 'conf.d'
too high. It may be useful to control for this by separately
setting <xref linkend="guc-autovacuum-work-mem"/>.
</para>
- <para>
- Note that for the collection of dead tuple identifiers,
- <command>VACUUM</command> is only able to utilize up to a maximum of
- <literal>1GB</literal> of memory.
- </para>
</listitem>
</varlistentry>

This is mentioned twice for two different GUCs -- need to remove the
other one, too. Other than that, I just have minor nits:

- * The major space usage for vacuuming is storage for the array of dead TIDs
+ * The major space usage for vacuuming is TID store, a storage for dead TIDs

I think I've helped edit this sentence before, but I still don't quite
like it. I'm thinking now "is storage for the dead tuple IDs".

- * set upper bounds on the number of TIDs we can keep track of at once.
+ * set upper bounds on the maximum memory that can be used for keeping track
+ * of dead TIDs at once.

I think "maximum" is redundant with "upper bounds".

I also feel the commit message needs more "meat" -- we need to clearly
narrate the features and benefits. I've attached how I would write it,
but feel free to use what you like to match your taste.

I've marked it Ready for Committer.