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: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.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>, Greg Nancarrow <gregn4422@gmail.com>
Date: 2021-09-24T13:18:16Z
Lists: pgsql-hackers 
On Fri, Sep 24, 2021 at 5:53 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Tuesday, September 21, 2021 12:53 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > I've attached the updated version patches. Please review them.
>
> Thanks for updating the patch,
> here are a few comments on the v14-0001 patch.

Thank you for the comments!

>
> 1)
> +                               hash_ctl.keysize = sizeof(Oid);
> +                               hash_ctl.entrysize = sizeof(SubscriptionRelState);
> +                               not_ready_rels_htab = hash_create("not ready relations in subscription",
> +                                                                                                 64,
> +                                                                                                 &hash_ctl,
> +                                                                                                 HASH_ELEM | HASH_BLOBS);
> +
>
> ISTM we can pass list_length(not_ready_rels_list) as the nelem to hash_create.

As Amit pointed out, it seems not necessary to build a temporary hash
table for this purpose.

>
> 2)
>
> +       /*
> +        * Search for all the dead subscriptions and error entries in stats
> +        * hashtable and tell the stats collector to drop them.
> +        */
> +       if (subscriptionHash)
> +       {
> ...
> +               HTAB       *htab;
> +
>
> It seems we already delacre a "HTAB *htab;" in function pgstat_vacuum_stat(),
> can we use the existing htab here ?

Right. Will remove it.

>
>
> 3)
>
>         PGSTAT_MTYPE_RESETREPLSLOTCOUNTER,
> +       PGSTAT_MTYPE_SUBSCRIPTIONERR,
> +       PGSTAT_MTYPE_SUBSCRIPTIONERRRESET,
> +       PGSTAT_MTYPE_SUBSCRIPTIONERRPURGE,
> +       PGSTAT_MTYPE_SUBSCRIPTIONPURGE,
>         PGSTAT_MTYPE_AUTOVAC_START,
>
> Can we append these values at the end of the Enum struct which won't affect the
> other Enum values.

Yes, I'll move them to the end of the Enum struct.

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