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

Dilip Kumar <dilipbalaut@gmail.com>

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: 2020-06-29T10:54:13Z
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, Jun 22, 2020 at 4:30 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Mon, Jun 22, 2020 at 4:26 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Thu, Jun 18, 2020 at 9:02 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > >
> > > Yes, I have made the changes.  Basically, now I am only using the
> > > XLOG_XACT_INVALIDATIONS for generating all the invalidation messages.
> > > So whenever we are getting the new set of XLOG_XACT_INVALIDATIONS, we
> > > are directly appending it to the txn->invalidations.  I have tested
> > > the XLOG_INVALIDATIONS part but while sending this mail I realized
> > > that we could write some automated test for the same.
> > >
> >
> > Can you share how you have tested it?
> >
> > >  I will work on
> > > that soon.
> > >
> >
> > Cool, I think having a regression test for this will be a good idea.
> >
>
> Other than above tests, can we somehow verify that the invalidations
> generated at commit time are the same as what we do with this patch?
> We have verified with individual commands but it would be great if we
> can verify for the regression tests.

I have verified this using a few random test cases.  For verifying
this I have made some temporary code changes with an assert as shown
below.  Basically, on DecodeCommit we call
ReorderBufferAddInvalidations function only for an assert checking.

-void
 ReorderBufferAddInvalidations(ReorderBuffer *rb, TransactionId xid,
                                                          XLogRecPtr
lsn, Size nmsgs,
-
SharedInvalidationMessage *msgs)
+
SharedInvalidationMessage *msgs, bool commit)
 {
        ReorderBufferTXN *txn;

        txn = ReorderBufferTXNByXid(rb, xid, true, NULL, lsn, true);
-
+       if (commit)
+       {
+               Assert(txn->ninvalidations == nmsgs);
+               return;
+       }

The result is that for a normal local test it works fine.  But with
regression suit, it hit an assert at many places because if the
rollback of the subtransaction is involved then at commit time
invalidation messages those are not logged whereas with command time
invalidation those are logged.

As of now, I have only put assert on the count,  if we need to verify
the exact messages then we might need to somehow categories the
invalidation messages because the ordering of the messages will not be
the same.  For testing this we will have to arrange them by category
i.e relcahce, catcache and then we can compare them.


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