Horton

Re: Skipping logical replication transactions on subscriber side

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Noah Misch <noah@leadboat.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Euler Taveira <euler@eulerto.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "David G. Johnston" <david.g.johnston@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, vignesh C <vignesh21@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-04-04T01:28:30Z
Lists: pgsql-hackers

Attachments

On Sun, Apr 3, 2022 at 9:45 AM Noah Misch <noah@leadboat.com> wrote:
>
> On Sat, Apr 02, 2022 at 08:44:45PM +0900, Masahiko Sawada wrote:
> > On Sat, Apr 2, 2022 at 7:04 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > On Sat, Apr 2, 2022 at 1:43 PM Noah Misch <noah@leadboat.com> wrote:
> > > > Some options:
> > > > - Move subskiplsn after subdbid, so it's always aligned anyway.  I've
> > > >   confirmed that this lets the test pass, in 44s.
> > > > - Move subskiplsn to the CATALOG_VARLEN section, despite its fixed length.
> > >
> > > +1 to any one of the above. I mildly prefer the first option as that
> > > will allow us to access the value directly instead of going via
> > > SysCacheGetAttr but I am fine either way.
> >
> > +1. I also prefer the first option.
>
> Sounds good to me.

I've attached the patch for the first option.

> - Introduce a new typalign value suitable for uint64.  This is more intrusive,
>   but it's more future-proof.  Looking beyond catalog columns, it might
>   improve performance by avoiding unaligned reads.

The third option would be a good item for PG16 or later.

Regards,

-- 
Masahiko Sawada
EDB:  https://www.enterprisedb.com/

Commits

  1. Test ALIGNOF_DOUBLE==4 compatibility under ALIGNOF_DOUBLE==8.

  2. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  3. Add ALTER SUBSCRIPTION ... SKIP.

  4. Optionally disable subscriptions on error.

  5. Update docs of logical replication for commit 8d74fc96db.

  6. Respect permissions within logical replication.

  7. Fix regression test failure caused by commit 8d74fc96db.

  8. Add a view to show the stats of subscription workers.

  9. Add logical change details to logical replication worker errcontext.

  10. Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

  11. Fix typo in protocol.sgml.

  12. Remove unused argument in apply_handle_commit_internal().

  13. Fix replication of in-progress transactions in tablesync worker.

  14. Reorder pg_sequence columns to avoid alignment issue