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: 2020-07-06T06:01:06Z
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 Sun, Jul 5, 2020 at 4:47 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Sat, Jul 4, 2020 at 11:35 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
>
> > 9.
> > +ReorderBufferHandleConcurrentAbort(ReorderBuffer *rb, ReorderBufferTXN *txn,
> > {
> > ..
> > + ReorderBufferToastReset(rb, txn);
> > + if (specinsert != NULL)
> > + ReorderBufferReturnChange(rb, specinsert);
> > ..
> > }
> >
> > Why do we need to do these here when we wouldn't have been done for
> > any exception other than ERRCODE_TRANSACTION_ROLLBACK?
>
> Because we are handling this exception "ERRCODE_TRANSACTION_ROLLBACK"
> gracefully and we are continuing with further decoding so we need to
> return this change back.
>

Okay, then I suggest we should do these before calling stream_stop and
also move ReorderBufferResetTXN after calling stream_stop  to follow a
pattern similar to try block unless there is a reason for not doing
so.  Also, it would be good if we can initialize specinsert with NULL
after returning the change as we are doing at other places.

> > 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?
>

No, I am also not able to reproduce it consistently but I think this
can fail if a subscriber sends the replay_location before actually
replaying the changes.  First, I thought that extra send_feedback we
have in apply_handle_stream_commit might have caused this but I guess
that can't happen because we need the commit time location for that
and we are storing the same at the end of apply_handle_stream_commit
after applying all messages.  I am not sure what is going on here.  I
think we somehow need to reproduce this or some variant of this test
consistently to find the root cause.

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