Horton

Re: AIO v2.5

Andres Freund <andres@anarazel.de>

View thread
From: Andres Freund <andres@anarazel.de>
To: Alexander Lakhin <exclusion@gmail.com>
Cc: Noah Misch <noah@leadboat.com>, pgsql-hackers@postgresql.org, Thomas Munro <thomas.munro@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Robert Haas <robertmhaas@gmail.com>, Jakub Wartak <jakub.wartak@enterprisedb.com>, Jelte Fennema-Nio <postgres@jeltef.nl>, Antonin Houska <ah@cybertec.at>
Date: 2025-04-07T16:20:15Z
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. aio: Fix assertion, clarify README

  2. aio: Fix reference to outdated name

  3. aio: Fix possible state confusions due to interrupt processing

  4. aio: Improve debug logging around waiting for IOs

  5. aio: Fix crash potential for pg_aios views due to late state update

  6. Increase BAS_BULKREAD based on effective_io_concurrency

  7. localbuf: Add Valgrind buffer access instrumentation

  8. aio: Make AIO more compatible with valgrind

  9. aio: Avoid spurious coverity warning

  10. tests: Fix incompatibility of test_aio with *_FORCE_RELEASE

  11. tests: Cope with WARNINGs during failed CREATE DB on windows

  12. aio: Add errcontext for processing I/Os for another backend

  13. aio: Add README.md explaining higher level design

  14. aio: Minor comment improvements

  15. aio: Add test_aio module

  16. aio: Add pg_aios view

  17. docs: Add acronym and glossary entries for I/O and AIO

  18. Enable IO concurrency on all systems

  19. read_stream: Introduce and use optional batchmode support

  20. docs: Reframe track_io_timing related docs as wait time

  21. bufmgr: Use AIO in StartReadBuffers()

  22. bufmgr: Implement AIO read support

  23. aio: Add WARNING result status

  24. Let caller of PageIsVerified() control ignore_checksum_failure

  25. pgstat: Allow checksum errors to be reported in critical sections

  26. Add errhint_internal()

  27. localbuf: Track pincount in BufferDesc as well

  28. aio, bufmgr: Comment fixes/improvements

  29. Fix mis-attribution of checksum failure stats to the wrong database

  30. aio: Implement support for reads in smgr/md/fd

  31. aio: Add io_method=io_uring

  32. aio: Add liburing dependency

  33. aio: Rename pgaio_io_prep_* to pgaio_io_start_*

  34. aio: Pass result of local callbacks to ->report_return

  35. aio: Be more paranoid about interrupts

  36. Redefine max_files_per_process to control additionally opened files

  37. aio: Change prefix of PgAioResultStatus values to PGAIO_RS_

  38. bufmgr: Improve stats when a buffer is read in concurrently

  39. aio: Add io_method=worker

  40. aio: Infrastructure for io_method=worker

  41. aio: Add core asynchronous I/O infrastructure

  42. aio: Basic subsystem initialization

  43. tests: Expand temp table tests to some pin related matters

  44. localbuf: Introduce FlushLocalBuffer()

  45. localbuf: Introduce TerminateLocalBufferIO()

  46. localbuf: Fix dangerous coding pattern in GetLocalVictimBuffer()

  47. localbuf: Introduce StartLocalBufferIO()

  48. localbuf: Introduce InvalidateLocalBuffer()

  49. Allow lwlocks to be disowned

  50. Make jsonb casts to scalar types translate JSON null to SQL NULL.

  51. bufmgr/smgr: Don't cross segment boundaries in StartReadBuffers()

  52. Use aux process resource owner in walsender

  53. bufmgr: Return early in ScheduleBufferTagForWriteback() if fsync=off

Hi,

On 2025-04-06 23:00:00 +0300, Alexander Lakhin wrote:
> 02.04.2025 14:58, Andres Freund wrote:
> When running multiple installcheck's against a single server (please find
> the ready-to-use script attached (I use more sophisticated version with
> additional patches to make installcheck pass cleanly, but that's not
> required for this case)), I've encountered an interesting error related to
> AIO/uring:
> iteration 8: Sun Apr  6 19:22:39 UTC 2025
> installchecks finished: Sun Apr  6 19:23:47 UTC 2025
> 2025-04-06 19:22:44.216 UTC [349525] LOG:  could not read blocks 0..0 in file "base/6179194/2606": Operation canceled
> 2025-04-06 19:22:44.216 UTC [349525] ERROR:  could not read blocks 0..0 in file "base/6179194/2606": Operation canceled

Thanks for the report, clearly something isn't right.


> It's reproduced better on tmpfs for me; probably you would need to increase
> NUM_INSTALLCHECKS/NUM_ITERATIONS for your machine.

I ran it for a while in a VM, it hasn't triggered yet. Neither on xfs nor on
tmpfs.


> server.log contains:
> 2025-04-06 19:22:44.215 UTC [38231] LOG:  checkpoint complete: wrote ...
> 2025-04-06 19:22:44.216 UTC [38231] LOG:  checkpoint starting: immediate force wait flush-all
> 2025-04-06 19:22:44.216 UTC [349525] LOG:  could not read blocks 0..0 in file "base/6179194/2606": Operation canceled
> 2025-04-06 19:22:44.216 UTC [349525] STATEMENT:  alter table parted_copytest
> attach partition parted_copytest_a1 for values in(1);
> 2025-04-06 19:22:44.216 UTC [349525] ERROR:  could not read blocks 0..0 in file "base/6179194/2606": Operation canceled
> 2025-04-06 19:22:44.216 UTC [349525] STATEMENT:  alter table parted_copytest
> attach partition parted_copytest_a1 for values in(1);

Hm. Does the failure vary between occurrences?
- is it always the same statement? Probably not?
- is it always 2606 (i.e. pg_constraint)?
- does the failure always happen around a checkpoint? If so, is it always
  immediate?
- I do assume it's always ECANCELED?


> I can reduce the testing procedure to something trivial, if it makes sense
> for you. Probably, the same effect can be also achieved with just pgbench...

That'd be very helpful!

Greetings,

Andres Freund