Horton

Re: AIO v2.5

Ranier Vilela <ranier.vf@gmail.com>

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From: Ranier Vilela <ranier.vf@gmail.com>
To: Andres Freund <andres@anarazel.de>
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: 2025-04-03T19:16:50Z
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 aio: Fix reference to outdated name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

Em qui., 3 de abr. de 2025 às 15:35, Andres Freund <andres@anarazel.de>
escreveu:

> Hi,
>
> On 2025-04-03 13:46:39 -0300, Ranier Vilela wrote:
> > Em qua., 2 de abr. de 2025 às 08:58, Andres Freund <andres@anarazel.de>
> > escreveu:
> >
> > > Hi,
> > >
> > > I've pushed fixes for 1) and 2) and am working on 3).
> > >
> > Coverity has one report about this.
> >
> > CID 1596092: (#1 of 1): Uninitialized scalar variable (UNINIT)
> > 13. uninit_use_in_call: Using uninitialized value result_one. Field
> > result_one.result is uninitialized when calling pgaio_result_report.
>
> Isn't this a rather silly thing to warn about for coverity?

Personally, I consider every warning to be important.


>   The field isn't
> used in pgaio_result_report().  It can't be a particularly rare thing to
> have
> struct fields that aren't always used?
>
Always considered a risk, someone may start using it.


>
>
> > Below not is a fix, but some suggestion:
> >
> > diff --git a/src/backend/storage/buffer/bufmgr.c
> > b/src/backend/storage/buffer/bufmgr.c
> > index 1c37d7dfe2..b0f9ce452c 100644
> > --- a/src/backend/storage/buffer/bufmgr.c
> > +++ b/src/backend/storage/buffer/bufmgr.c
> > @@ -6786,6 +6786,8 @@ buffer_readv_encode_error(PgAioResult *result,
> >   else
> >   result->status = PGAIO_RS_WARNING;
> >
> > + result->result = 0;
> > +
>
> That'd be completely wrong - and the tests indeed fail if you do that. The
> read might succeed with a warning (e.g. due to zero_damaged_pages) in which
> case the result still carries important information about how many blocks
> were
> successfully read.
>
That's exactly why it's not a patch.


>
>
> >   /*
> >   * The encoding is complicated enough to warrant cross-checking it
> against
> >   * the decode function.
> > @@ -6868,8 +6870,6 @@ buffer_readv_complete_one(PgAioTargetData *td,
> uint8
> > buf_off, Buffer buffer,
> >   /* Check for garbage data. */
> >   if (!failed)
> >   {
> > - PgAioResult result_one;
> > -
> >   if (!PageIsVerified((Page) bufdata, tag.blockNum, piv_flags,
> >   failed_checksum))
> >   {
> > @@ -6904,6 +6904,8 @@ buffer_readv_complete_one(PgAioTargetData *td,
> uint8
> > buf_off, Buffer buffer,
> >   */
> >   if (*buffer_invalid || *failed_checksum || *zeroed_buffer)
> >   {
> > + PgAioResult result_one;
> > +
> >   buffer_readv_encode_error(&result_one, is_temp,
> >    *zeroed_buffer,
> >    *ignored_checksum,
> >
> >
> > 1. I couldn't find the correct value to initialize the *result* field.
>
> It is not accessed in this path.  I guess we can just zero-initialize
> result_one to shut up coverity.
>
Very good.


>
>
> > 2. result_one can be reduced scope.
>
> True.
>
Ok.

best regards,
Ranier Vilela