Horton

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

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Amit Kapila <amit.kapila16@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: 2020-07-05T11:05:08Z
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 Tue, Jun 30, 2020 at 5:20 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Jun 30, 2020 at 10:13 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > On Tue, Jun 30, 2020 at 9:20 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > Can't we name the last parameter as 'commit_lsn' as that is how
> > > documentation in the patch spells it and it sounds more appropriate?
> >
> > You are right commit_lsn seems more appropriate here.
> >
> > > Also, is there a reason for assigning report_location and
> > > write_location differently than what we do in commit_cb_wrapper?
> > > Basically, assign those as txn->final_lsn and txn->end_lsn
> > > respectively.
> >
> > Yes, I think it should be handled in same way as commit_cb_wrapper.
> > Because before calling ReorderBufferStreamCommit in
> > ReorderBufferCommit, we are properly updating the final_lsn as well as
> > the end_lsn.
> >
>
> Okay, I have made these changes in the attached patch and there are
> few more changes in
> 0003-Extend-the-output-plugin-API-with-stream-methods.
> 1. In pg_decode_stream_message, for transactional messages, we were
> displaying message contents which is different from other streaming
> APIs.  I have changed it so that streaming API doesn't display message
> contents for transactional messages.

Ok, make sense.

> 2.
> + /* in streaming mode, stream_change_cb is required */
> + if (ctx->callbacks.stream_change_cb == NULL)
> + ereport(ERROR,
> + (errmsg("Output plugin supports streaming, but has not registered "
> + "stream_change_cb callback.")));
>
> The error messages seem a bit weird.  (a) doesn't include error code,
> (b) not in PG style. I have changed all the error messages to fix
> these two issues and change the message as well

ok

> 3. Rearranged the functions stream_* so that the optional functions
> are at the end and also arranged other functions in a way that looks
> more logical to me.

Make sense to me.

> 4. Updated comments, commit message, and edited docs in the patch.
>
> I have made a few changes in
> 0004-Gracefully-handle-concurrent-aborts-of-transacti as well.
> 1. The variable bsysscan was not being reset in case of error.  I have
> introduced a new function to reset both bsysscan and CheckXidAlive
> during transaction abort.  Also, snapmgr.c doesn't seem right place
> for these variables, so I moved them to xact.c.  I think this will
> make the initialization of CheckXidAlive during catch in
> ReorderBufferProcessTXN redundant.

That looks better.

> 2. Updated comments and commit message.
>
> Let me know what you think about the above changes.

All the above changes look good to me and I will include in the next version.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com