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: 2020-08-21T03:58:10Z
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 Fri, Aug 21, 2020 at 9:14 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Thu, Aug 20, 2020 at 5:42 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > On Thu, Aug 20, 2020 at 2:30 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > >
> > > Right, I think this can happen if one has changed those by BufFileSeek
> > > before doing truncate. We should fix that case as well.
> >
> > Right.
> >
> > > >  I will work on those along with your other comments and
> > > > submit the updated patch.
> >
> > I have fixed this in the attached patch along with your other
> > comments.  I have also attached a contrib module that is just used for
> > testing the truncate API.
> >
>
> Few comments:
> ==============
> +void
> +BufFileTruncateShared(BufFile *file, int fileno, off_t offset)
> {
> ..
> + if ((i != fileno || offset == 0) && i != 0)
> + {
> + SharedSegmentName(segment_name, file->name, i);
> + FileClose(file->files[i]);
> + if (!SharedFileSetDelete(file->fileset, segment_name, true))
> + ereport(ERROR,
> + (errcode_for_file_access(),
> + errmsg("could not delete shared fileset \"%s\": %m",
> + segment_name)));
> + numFiles--;
> + newOffset = MAX_PHYSICAL_FILESIZE;
> +
> + if (i == fileno)
> + newFile--;
> + }
>
> Here, shouldn't it be i <= fileno? Because we need to move back the
> curFile up to newFile whenever curFile is greater than newFile
>
> 2.
> + /*
> + * If the new location is smaller then the current location in file then
> + * we need to set the curFile and the curOffset to the new values and also
> + * reset the pos and nbytes.  Otherwise nothing to do.
> + */
> + else if ((newFile < file->curFile) ||
> + newOffset < file->curOffset + file->pos)
> + {
> + file->curFile = newFile;
> + file->curOffset = newOffset;
> + file->pos = 0;
> + file->nbytes = 0;
> + }
>
> Shouldn't there be && instead of || because if newFile is greater than
> curFile then there is no meaning to update it?
>

Wait, actually, it is not clear to me which case second condition
(newOffset < file->curOffset + file->pos) is trying to cover, so I
can't recommend anything for this. Can you please explain to me why
you have added the second condition in the above check?


-- 
With Regards,
Amit Kapila.