Horton

Re: Skipping logical replication transactions on subscriber side

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: Noah Misch <noah@leadboat.com>, Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Euler Taveira <euler@eulerto.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.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: 2022-04-06T08:53:28Z
Lists: pgsql-hackers 
On 02.04.22 10:13, Noah Misch wrote:
> uint64 and pg_lsn use TYPALIGN_DOUBLE.  For AIX, they really need a typalign
> corresponding to ALIGNOF_LONG.  Hence, the C struct layout doesn't match the
> tuple layout.  Columns potentially affected:
> 
> [local] test=*# select attrelid::regclass, attname from pg_attribute a join pg_class c on c.oid = attrelid where attalign = 'd' and relkind = 'r' and attnotnull and attlen <> -1;
>      attrelid     │   attname
> ─────────────────┼──────────────
>   pg_sequence     │ seqstart
>   pg_sequence     │ seqincrement
>   pg_sequence     │ seqmax
>   pg_sequence     │ seqmin
>   pg_sequence     │ seqcache
>   pg_subscription │ subskiplsn
> (6 rows)
> 
> The pg_sequence fields evade trouble, because there's exactly eight bytes (two
> oids) before them.

Yes, we carefully did this when we ran into this the last time.  See 
<https://www.postgresql.org/message-id/flat/76ce2ca3-40f2-d291-eae2-17b599f29ba0%402ndquadrant.com#cf1313adff98e1d5e1ca789497898310> 
and commit f3b421da5f4addc95812b9db05a24972b8fd9739.

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