Horton

Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Erik Rijkers <er@xs4all.nl>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-07-13T06:00:23Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Tighten the concurrent abort check during decoding.

  2. Improve hash_create()'s API for some added robustness.

  3. Use HASH_BLOBS for xidhash.

  4. Fix initialization of RelationSyncEntry for streaming transactions.

  5. Remove unused function declaration in logicalproto.h.

  6. Add additional tests to test streaming of in-progress transactions.

  7. Fix inline marking introduced in commit 464824323e.

  8. Add support for streaming to built-in logical replication.

  9. Fix the SharedFileSetUnregister API.

  10. Fix comment in procarray.c

  11. Suppress compiler warning in non-cassert builds.

  12. Extend the BufFile interface.

  13. Mark a few logical decoding related variables with PGDLLIMPORT.

  14. Implement streaming mode in ReorderBuffer.

  15. Extend the logical decoding output plugin API with stream methods.

  16. WAL Log invalidations at command end with wal_level=logical.

  17. Immediately WAL-log subtransaction and top-level XID association.

  18. Allow logical replication to transfer data in binary format.

  19. Only superuser can set sslcert/sslkey in postgres_fdw user mappings

  20. Track statistics for spilling of changes from ReorderBuffer.

  21. Add logical_decoding_work_mem to limit ReorderBuffer memory usage.

  22. logical decoding: process ASSIGNMENT during snapshot build

  23. Emit invalidations to standby for transactions without xid.

On Mon, Jul 13, 2020 at 10:47 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Sun, Jul 12, 2020 at 9:56 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > On Mon, Jul 6, 2020 at 11:43 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > >
> > > On Mon, Jul 6, 2020 at 11:31 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > >
> > >
> > > > > > 10.  I have got the below failure once.  I have not investigated this
> > > > > > in detail as the patch is still under progress.  See, if you have any
> > > > > > idea?
> > > > > > #   Failed test 'check extra columns contain local defaults'
> > > > > > #   at t/013_stream_subxact_ddl_abort.pl line 81.
> > > > > > #          got: '2|0'
> > > > > > #     expected: '1000|500'
> > > > > > # Looks like you failed 1 test of 2.
> > > > > > make[2]: *** [check] Error 1
> > > > > > make[1]: *** [check-subscription-recurse] Error 2
> > > > > > make[1]: *** Waiting for unfinished jobs....
> > > > > > make: *** [check-world-src/test-recurse] Error 2
> > > > >
> > > > > Even I got the failure once and after that, it did not reproduce.  I
> > > > > have executed it multiple time but it did not reproduce again.  Are
> > > > > you able to reproduce it consistently?
> > > > >
> > > >
...
..
> >
> > I think the reason for the failure is that we are not setting
> > remote_final_lsn, in the streaming mode.  I have put multiple logs and
> > executed in log and from logs it appeared that some of the logical wal
> > did not get replayed due to below check in
> > should_apply_changes_for_rel.
> > return (rel->state == SUBREL_STATE_READY || (rel->state ==
> > SUBREL_STATE_SYNCDONE && rel->statelsn <= remote_final_lsn));
> >
> > I still need to do the detailed analysis that why does this fail in
> > some cases,  basically, most of the time the rel->state is
> > SUBREL_STATE_READY so this check passes but whenever the state is
> > SUBREL_STATE_SYNCDONE it failed because we never update
> > remote_final_lsn.  I will try to set this value in
> > apply_handle_stream_commit and see whether it ever fails or not.
>
> I have verified that after setting the remote_final_lsn in the
> apply_handle_stream_commit, I don't see that regression failure in
> over 70 runs whereas without that change it failed 6 times in 50 runs.
>

Your analysis and fix seem correct to me.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com