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: vignesh C <vignesh21@gmail.com>
Cc: Greg Nancarrow <gregn4422@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-11-18T13:59:56Z
Lists: pgsql-hackers 
On Wed, Nov 17, 2021 at 7:46 PM vignesh C <vignesh21@gmail.com> wrote:
>
> On Tue, Nov 16, 2021 at 12:01 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > On Mon, Nov 15, 2021 at 11:43 PM vignesh C <vignesh21@gmail.com> wrote:
> > >
> > > On Mon, Nov 15, 2021 at 2:48 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > > >
> > > > On Mon, Nov 15, 2021 at 4:49 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
> > > > >
> > > > > On Mon, Nov 15, 2021 at 1:49 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > > > > >
> >
> > Right. I've fixed this issue and attached an updated patch.
>
> Few comments:

Thank you for the comments!

> 1) should we set subwentry to NULL to handle !create && !found case
> or we could return NULL similar to the earlier function.
> +static PgStat_StatSubWorkerEntry *
> +pgstat_get_subworker_entry(PgStat_StatDBEntry *dbentry, Oid subid,
> Oid subrelid,
> +                                                  bool create)
> +{
> +       PgStat_StatSubWorkerEntry *subwentry;
> +       PgStat_StatSubWorkerKey key;
> +       bool            found;
> +       HASHACTION      action = (create ? HASH_ENTER : HASH_FIND);
> +
> +       key.subid = subid;
> +       key.subrelid = subrelid;
> +       subwentry = (PgStat_StatSubWorkerEntry *)
> hash_search(dbentry->subworkers,
> +
>                                            (void *) &key,
> +
>                                            action, &found);
> +
> +       /* If not found, initialize the new one */
> +       if (create && !found)

It's better to return NULL if !create && !found. WIll fix.

>
> 2) Should we keep the line width to 80 chars:
> +/* ----------
> + * PgStat_MsgSubWorkerError            Sent by the apply worker or
> the table sync worker to
> + *                                                             report
> the error occurred during logical replication.
> + * ----------
> + */
> +#define PGSTAT_SUBWORKERERROR_MSGLEN 256
> +typedef struct PgStat_MsgSubWorkerError
> +{

Hmm, pg_indent seems not to fix it. Anyway, will fix.

I'll fix an updated patch.

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