Horton

Re: Table AM Interface Enhancements

Pavel Borisov <pashkin.elfe@gmail.com>

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From: Pavel Borisov <pashkin.elfe@gmail.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Japin Li <japinli@hotmail.com>, Mark Dilger <mark.dilger@enterprisedb.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-04-08T07:17:51Z
Lists: pgsql-hackers 
Hi, Alexander and Andres!

On Mon, 8 Apr 2024 at 03:25, Alexander Korotkov <aekorotkov@gmail.com>
wrote:

> Hi,
>
> On Mon, Apr 8, 2024 at 12:40 AM Andres Freund <andres@anarazel.de> wrote:
> > On 2024-03-30 23:33:04 +0200, Alexander Korotkov wrote:
> > > I've pushed 0001, 0002 and 0006.
> >
> > I briefly looked at 27bc1772fc81 and I don't think the state post this
> commit
> > makes sense. Before this commit another block based AM could implement
> analyze
> > without much code duplication. Now a large portion of analyze.c has to be
> > copied, because they can't stop acquire_sample_rows() from calling
> > heapam_scan_analyze_next_block().
> >
> > I'm quite certain this will break a few out-of-core AMs in a way that
> can't
> > easily be fixed.
>
> I was under the impression there are not so many out-of-core table
> AMs, which have non-dummy analysis implementations.  And even if there
> are some, duplicating acquire_sample_rows() isn't a big deal.
>
> But given your feedback, I'd like to propose to keep both options
> open.  Turn back the block-level API for analyze, but let table-AM
> implement its own analyze function.  Then existing out-of-core AMs
> wouldn't need to do anything (or probably just set the new API method
> to NULL).
>
I think that providing both new and old interface functions for block-based
and non-block based custom am is an excellent compromise.

The patch v1-0001-Turn-back.. is mainly an undo of part of the 27bc1772fc81
that had turned off _analyze_next_tuple..analyze_next_block for external
callers. If some extensions are already adapted to the old interface
functions, they are free to still use it.

> And even for non-block based AMs, the new interface basically requires
> > reimplementing all of analyze.c.
> .
> Non-lock base AM needs to just provide an alternative implementation
> for what acquire_sample_rows() does.  This seems like reasonable
> effort for me, and surely not reimplementing all of analyze.c.
>
I agree.

Regards,
Pavel Borisov
Supabase

Commits

  1. Remove extra comment at TableAmRoutine.scan_analyze_next_block

  2. revert: Generalize relation analyze in table AM interface

  3. Revert: Allow table AM to store complex data structures in rd_amcache

  4. Revert: Allow table AM tuple_insert() method to return the different slot

  5. Revert: Allow locking updated tuples in tuple_update() and tuple_delete()

  6. Revert: Let table AM insertion methods control index insertion

  7. Revert: Custom reloptions for table AM

  8. Provide a way block-level table AMs could re-use acquire_sample_rows()

  9. Custom reloptions for table AM

  10. Use streaming I/O in ANALYZE.

  11. Revert "Custom reloptions for table AM"

  12. Let table AM insertion methods control index insertion

  13. Generalize relation analyze in table AM interface

  14. Improve error message for tts_(virtual|minimal)_is_current_xact_tuple

  15. Add comments on some MinimalTupleSlots methods usage

  16. Add TupleTableSlotOps.is_current_xact_tuple() method

  17. Allow table AM tuple_insert() method to return the different slot

  18. Allow table AM to store complex data structures in rd_amcache