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: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Erik Rijkers <er@xs4all.nl>, Jeff Janes <jeff.janes@gmail.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-15T02:54:44Z
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, Sep 14, 2020 at 9:42 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Amit Kapila <amit.kapila16@gmail.com> writes:
> > The attached patch will fix the issue. What do you think?
>
> I think it'd be cleaner to separate the initialization of a new entry from
> validation altogether, along the lines of
>
>     /* Find cached function info, creating if not found */
>     oldctx = MemoryContextSwitchTo(CacheMemoryContext);
>     entry = (RelationSyncEntry *) hash_search(RelationSyncCache,
>                                               (void *) &relid,
>                                               HASH_ENTER, &found);
>     MemoryContextSwitchTo(oldctx);
>     Assert(entry != NULL);
>
>     if (!found)
>     {
>         /* immediately make a new entry valid enough to satisfy callbacks */
>         entry->schema_sent = false;
>         entry->streamed_txns = NIL;
>         entry->replicate_valid = false;
>         /* are there any other fields we should clear here for safety??? */
>     }
>

If we want to separate validation then we need to initialize other
fields like 'pubactions' and 'publish_as_relid' as well. I think it
will be better to arrange it the way you are suggesting. So, I will
change it along with other fields that required initialization.

>     /* Fill it in if not valid */
>     if (!entry->replicate_valid)
>     {
>         List       *pubids = GetRelationPublications(relid);
>         ...
>
> BTW, unless someone has changed the behavior of dynahash when I
> wasn't looking, those MemoryContextSwitchTos shown above are useless.
>

As far as I can see they are useless in this case but I think they
might be required in case the user provides its own allocator function
(using HASH_ALLOC). So, we can probably remove those from here?

> Also, why does the comment refer to a "function" entry?
>

It should be "relation" instead. I'll take care of changing this as well.

-- 
With Regards,
Amit Kapila.