Horton

Re: AIO v2.5

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Antonin Houska <ah@cybertec.at>
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>
Date: 2025-03-25T01:18:06Z
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 aio: Fix reference to outdated name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

Attachments

Hi,

Attached v2.12, with the following changes:

- Pushed the max_files_per_process change

  I plan to look at what parts of Jelte's change is worth doing ontop.

  Thanks for the review Noah.


- Rebased over Thomas' commit of the remaining read stream changes

  Yay!


- Addressed Noah's review comments


- Added another test to test_aio/, to test that changing io_workers while
  running works, and that workers are restarted if terminated

  Written by Bilal


- Made InvalidateLocalBuffer wait for IO if necessary

  As reported / suggested by Noah


- Added tests for dropping tables with ongoing IO

  This failed, as Noah predicted, without the InvalidateLocalBuffer() change.


- Added a commit to explicitly hold interrupts in workers after
  pgaio_io_reopen()

  As suggested by Noah.


- Added a commit to fix a logic error around what gets passed to
  ioh->report_return - this lead to temporary buffer validation errors not
  being reported

  Discovered while extending the tests, as noted in the next point.

  I could see a few different "formulations" of this change (e.g. the
  report_return stuff could be populated by pgaio_io_call_complete_local()
  instead), but I don't think it matters much.


- Add temporary table coverage to test_aio

  This required hanged test_aio.c to cope with temporary tables as well.


- io_uring tests don't run anymore when built with EXEC_BACKEND and liburing
  enabled


- Split the read stream patch into two

  Noah, quite rightly, pointed out that it's not safe to use batching if the
  next-block callback may block (or start its own batch). The best idea seems
  to be to make users of read stream opt-in to batching.  I've done that in a
  patch that uses where it seems safe without doing extra work. See also the
  commit message.


- Added a commit to add I/O, Asynchronous I/O glossary and acronym entries


- Docs for pg_aios


- Renamed pg_aios.offset to off, to avoid use of a keyword


- Updated the io_uring wait event name while waiting for IOs to complete to
  AIO_IO_URING_COMPLETION and updated the description of AIO_IO_COMPLETION to
  "Waiting for another process to complete IO."

  I think this is a mix of different suggestions by Noah.


TODO:


- There are more tests in test_aio that should be expanded to run for temp
  tables as well, not just normal tables


- Add an explicit test for the checksum verification in the completion callback

  There is an existing test for testing an invalid page due to page header
  verification in test_aio, but not for checksum failures.

  I think it's indirectly covered (e.g. in amcheck), but seems better to test
  it explicitly.

  Wonder if it's worth adding some coverage for when checksums are disabled?
  Probably not necessary?


Greetings,

Andres Freund