Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>, Dilip Kumar <dilipbalaut@gmail.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: 2020-09-13T21:38:43Z
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.

Amit Kapila <amit.kapila16@gmail.com> writes:
> Pushed.

Observe the following reports:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=idiacanthus&dt=2020-09-13%2016%3A54%3A03
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=desmoxytes&dt=2020-09-10%2009%3A08%3A03
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=komodoensis&dt=2020-09-05%2020%3A22%3A02
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dragonet&dt=2020-09-04%2001%3A52%3A03
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dragonet&dt=2020-09-03%2020%3A54%3A04

These are all on HEAD, and all within the last ten days, and I see
nothing comparable in any branch before that.  So it's hard to avoid
the conclusion that somebody broke something about ten days ago.

None of these animals provided gdb backtraces; but we do have a built-in
trace from several, and they all look like pgoutput.so is trying to
list_free() garbage, somewhere inside a relcache invalidation/rebuild
scenario:

TRAP: FailedAssertion("list->length > 0", File: "/home/bf/build/buildfarm-idiacanthus/HEAD/pgsql.build/../pgsql/src/backend/nodes/list.c", Line: 68)
postgres: publisher: walsender bf [local] idle(ExceptionalCondition+0x57)[0x9081f7]
postgres: publisher: walsender bf [local] idle[0x6bcc70]
postgres: publisher: walsender bf [local] idle(list_free+0x11)[0x6bdc01]
/home/bf/build/buildfarm-idiacanthus/HEAD/pgsql.build/tmp_install/home/bf/build/buildfarm-idiacanthus/HEAD/inst/lib/postgresql/pgoutput.so(+0x35d8)[0x7fa4c5a6f5d8]
postgres: publisher: walsender bf [local] idle(LocalExecuteInvalidationMessage+0x15b)[0x8f0cdb]
postgres: publisher: walsender bf [local] idle(ReceiveSharedInvalidMessages+0x4b)[0x7bca0b]
postgres: publisher: walsender bf [local] idle(LockRelationOid+0x56)[0x7c19e6]
postgres: publisher: walsender bf [local] idle(relation_open+0x1c)[0x4a2d0c]
postgres: publisher: walsender bf [local] idle(table_open+0x6)[0x524486]
postgres: publisher: walsender bf [local] idle[0x9017f2]
postgres: publisher: walsender bf [local] idle[0x8fabd4]
postgres: publisher: walsender bf [local] idle[0x8fa58a]
postgres: publisher: walsender bf [local] idle(RelationCacheInvalidateEntry+0xaf)[0x8fbdbf]
postgres: publisher: walsender bf [local] idle(LocalExecuteInvalidationMessage+0xec)[0x8f0c6c]
postgres: publisher: walsender bf [local] idle(ReceiveSharedInvalidMessages+0xcb)[0x7bca8b]
postgres: publisher: walsender bf [local] idle(LockRelationOid+0x56)[0x7c19e6]
postgres: publisher: walsender bf [local] idle(relation_open+0x1c)[0x4a2d0c]
postgres: publisher: walsender bf [local] idle(table_open+0x6)[0x524486]
postgres: publisher: walsender bf [local] idle[0x8ee8b0]

010_truncate.pl itself hasn't changed meaningfully in a good long time.
However, I see that 464824323 added a whole boatload of code to
pgoutput.c, and the timing is right for that commit to be the culprit,
so that's what I'm betting on.

Probably this requires a relcache inval at the wrong time;
although we have recent passes from CLOBBER_CACHE_ALWAYS animals,
so that can't be the whole triggering condition.  I wonder whether
it is relevant that all of the complaining animals are JIT-enabled.

			regards, tom lane