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: 2025-03-18T20:12:18Z
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 aio: Fix reference to outdated name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 is v2.10, with the following changes:

- committed core AIO infrastructure patch

  A few cosmetic changes


- committed io_method=worker

  Two non-cosmetic changes:

  - The shmem allocation functions over-estimated the amount of shared memory
    required.

  - pgaio_worker_shmem_init() should initialize up to MAX_IO_WORKERS, not just
    io_workers, since the latter is intentionally PGC_SIGHUP (found by Thomas)


- Bunch of typo fixes found by searching for repeated words

  Thomas found one and then I searched for more.


- Added Melanie's patch to allow effective_io_concurrency to be set on windows etc


- Fixed a reference to an outdated function reference (thanks to Bilal)


- Reordered patches to be a bit more in dependency order

  E.g. "bufmgr: Implement AIO read support" doesn't depend on Thomas' "buffer
  forwarding" patches and thus can be commited before those go in.


Next steps:

- Decide what to do about the smgr interrupt issue

  I guess it could be deferred, based on the argument it only matters with a
  sufficiently high debug level, but I don't feel comfortable with that.

  I think it'd be reasonable to just go with the patch I sent on the other
  thread (and included here).


- Get somebody to look at
  "bufmgr: Improve stats when buffer was read in concurrently"

  This arguably fixes a bug, or just weird behaviour, on master.


- Address the set_max_safe_fds() issue and once resolved, commit io_uring
  method

  Can happen concurrently with next steps


- Commit "aio: Implement support for reads in smgr/md/fd"


- Get somebody to do one more pass at bufmgr related commits, I think they
  could use a less in-the-weeds eye.

  That's the following commits:
  - localbuf: Track pincount in BufferDesc as well
  - bufmgr: Implement AIO read support
  - bufmgr: Use AIO in StartReadBuffers()
  - aio: Basic read_stream adjustments for real AIO


Questions / Unresolved:

- Write support isn't going to land in 18, but there is a tiny bit of code
  regarding writes in the code for bufmgr IO. I guess I could move that to a
  later commit?

  I'm inclined to leave it, the structure of the code only really makes
  knowing that it's going to be shared between reads & writes.


- pg_aios view name


Greetings,

Andres Freund