Horton

Re: shared-memory based stats collector

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Cc: alvherre@2ndquadrant.com, andres@anarazel.de, ah@cybertec.at, magnus@hagander.net, robertmhaas@gmail.com, tgl@sss.pgh.pa.us, pgsql-hackers@postgresql.org
Date: 2018-11-13T15:35:27Z
Lists: pgsql-hackers 
On Mon, 2018-11-12 at 20:10 +0900, Kyotaro HORIGUCHI wrote:
> At Fri, 9 Nov 2018 14:16:31 +0100, Tomas Vondra <
> tomas.vondra@2ndquadrant.com> wrote in <
> 803f2d96-3b4b-f357-9a2e-45443212f13d@2ndquadrant.com>
> > 
> > 
> > On 11/9/18 9:33 AM, Kyotaro HORIGUCHI wrote:
> > > Hello. This is rebased version.
> > > At Thu, 8 Nov 2018 16:06:49 +0100, Tomas Vondra
> > > <tomas.vondra@2ndquadrant.com> wrote in
> > > <de249c3f-79c9-b75c-79a3-5e2d008548a8@2ndquadrant.com>
> > >> However a quite a few extensions in contrib seem are broken now.
> It
> > >> seems fixing it is as simple as including the new bestatus.h
> next to
> > >> pgstat.h.
> > > The additional 0009 does that.
> > > 
> > 
> > That does fix it, indeed. But the break happens in 0003, so that's
> > where the fixes should be moved - I've tried to simply apply 0009
> > right after 0003, but that does not seem to work because bestatus.h
> > does not exist at that point yet :-/
> 
> Sorry, I misunderstood you. The real reason for breaking 0003 as
> you saw was the result I just removed PG_STAT_TMP_DIR. 0005 fixes
> that later. I (half-intentionally) didin't keep soundness of the
> source tree at v8-0003 and v8-0008.
> 
> > The current split into 8 parts seems quite sensible to me, i.e.
> that's
> > how it might get committed eventually. That however means each part
> > needs to be correct on it's own (hence fixes in 0009 are a
> problem).
> 
> Thanks. I neatended up the patchset so that individual patch
> keeps source buildable and doesn't break programs' behaviors.
> 

OK, thanks. I'll take a look. I also plan to do much more testing, both
for correctness and performance - it's quite piece of functionality.

If everything goes well I'd like to get this committed by the end of
January CF (with some of the initial parts in this CF, possibly).


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Improve comment about dropped entries in pgstat.c

  2. Fix temporary memory leak in system table index scans

  3. pgstat: set timestamps of fixed-numbered stats after a crash.

  4. pgstat: Update docs to match the shared memory stats reality.

  5. pgstat: Hide instability in stats.spec with -DCATCACHE_FORCE_RELEASE.

  6. pgstat: add/extend tests for resetting various kinds of stats.

  7. Add minimal tests for recovery conflict handling.

  8. pgstat: test stats interactions with physical replication.

  9. pgstat: add tests for handling of restarts, including crashes.

  10. pgstat: add tests for transaction behaviour, 2PC, function stats.

  11. pgstat: add pg_stat_have_stats() test helper.

  12. pgstat: add pg_stat_force_next_flush(), use it to simplify tests.

  13. pgstat: move pgstat.c to utils/activity.

  14. pgstat: store statistics in shared memory.

  15. pgstat: remove stats_temp_directory.

  16. pgstat: rename STATS_COLLECTOR GUC group to STATS_CUMULATIVE.

  17. pgstat: revise replication slot API in preparation for shared memory stats.

  18. pgstat: scaffolding for transactional stats creation / drop.

  19. pgstat: introduce PgStat_Kind enum.

  20. pgstat: prepare APIs used by pgstatfuncs for shared memory stats.

  21. pgstat: add pgstat_copy_relation_stats().

  22. pgstat: rename some pgstat_send_* functions to pgstat_report_*.

  23. pgstat: stats collector references in comments.

  24. pgstat: move transactional code into pgstat_xact.c.

  25. dsm: allow use in single user mode.

  26. dshash: revise sequential scan support.

  27. pgstat: remove some superflous comments from pgstat.h.

  28. pgstat: reorder pgstat.[ch] contents.

  29. pgstat: split different types of stats into separate files.

  30. pgstat: introduce pgstat_relation_should_count().

  31. pgstat: separate "xact level" handling out of relation specific functions.

  32. pgstat: rename pgstat_initstats() to pgstat_relation_init().

  33. pgstat: split out WAL handling from pgstat_{initialize,report_stat}.

  34. pgstat: run pgindent on pgstat.c/h.

  35. pgstat: split relation, database handling out of pgstat_report_stat().

  36. Move code around in StartupXLOG().

  37. pgstat: Prepare to use mechanism for truncated rels also for droppped rels.

  38. pgstat: Split out relation stats handling from AtEO[Sub]Xact_PgStat() etc.

  39. pgstat: Schedule per-backend pgstat shutdown via before_shmem_exit().

  40. Schedule ShutdownXLOG() in single user mode using before_shmem_exit().

  41. Make parallel worker shutdown complete entirely via before_shmem_exit().

  42. pgstat: Bring up pgstat in BaseInit() to fix uninitialized use of pgstat by AV.

  43. pgstat: split reporting/fetching of bgwriter and checkpointer stats.

  44. Split backend status and progress related functionality out of pgstat.c.

  45. Split wait event related code from pgstat.[ch] into wait_event.[ch].

  46. Make archiver process an auxiliary process.

  47. Force to send remaining WAL stats to the stats collector at walwriter exit.

  48. Add pg_stat_database counters for sessions and session time

  49. Collect statistics about SLRU caches

  50. Don't run atexit callbacks in quickdie signal handlers.

  51. Create a "fast path" for acquiring weak relation locks.