Re: logical decoding and replication of sequences, take 2

On Wed, Mar 1, 2023 at 1:02 AM Tomas Vondra <tomas.vondra@enterprisedb.com>
wrote:
> here's a rebased patch to make cfbot happy, dropping the first part that
> is now unnecessary thanks to 7fe1aa991b.

Hi Tomas,

I'm looking into doing some "in situ" testing, but for now I'll mention
some minor nits I found:

0001

+ * so we simply do a lookup (the sequence is identified by relfilende). If

relfilenode? Or should it be called a relfilelocator, which is the
parameter type? I see some other references to relfilenode in comments and
commit message, and I'm not sure which need to be updated.

+ /* XXX Maybe check that we're still in the same top-level xact? */

Any ideas on what should happen here?

+ /* XXX how could we have sequence change without data? */
+ if(!datalen || !tupledata)
+ elog(ERROR, "sequence decode missing tuple data");

Since the ERROR is new based on feedback, we can get rid of XXX I think.

More generally, I associate XXX comments to highlight problems or
unpleasantness in the code that don't quite rise to the level of FIXME, but
are perhaps more serious than "NB:", "Note:", or "Important:"

+ * When we're called via the SQL SRF there's already a transaction

I see this was copied from existing code, but I found it confusing -- does
this function have a stable name?

+ /* Only ever called from ReorderBufferApplySequence, so transational. */

Typo: transactional

0002

I see a few SERIAL types in the tests but no GENERATED ... AS IDENTITY --
not sure if it matters, but seems good for completeness.

Reminder for later: Patches 0002 and 0003 still refer to 0da92dc530, which
is a reverted commit -- I assume it intends to refer to the content of 0001?

--
John Naylor
EDB: http://www.enterprisedb.com