Re: Table AM Interface Enhancements

Pavel Borisov <pashkin.elfe@gmail.com>

From: Pavel Borisov <pashkin.elfe@gmail.com>
To:
Cc: Alexander Korotkov <aekorotkov@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-11-29T13:55:38Z
Lists: pgsql-hackers
Hi, Alexander!

> I'm planning to review some of the other patches from the current patchset
> soon.
>

I've looked into the patch 0003.
The patch looks in good shape and is uncontroversial to me. Making memory
structures to be dynamically allocated is simple enough and it allows to
store complex data like lists etc. I consider places like this that expect
memory structures to be flat and allocated at once are because the was no
need in more complex ones previously. If there is a need for them, I think
they could be added without much doubt, provided the simplicity of the
change.

For the code:
+static inline void
+table_free_rd_amcache(Relation rel)
+{
+ if (rel->rd_tableam && rel->rd_tableam->free_rd_amcache)
+ {
+ rel->rd_tableam->free_rd_amcache(rel);
+ }
+ else
+ {
+ if (rel->rd_amcache)
+ pfree(rel->rd_amcache);
+ rel->rd_amcache = NULL;
+ }

here I suggest adding Assert(rel->rd_amcache == NULL) (or maybe better an
error report) after calling free_rd_amcache to be sure the custom
implementation has done what it should do.

Also, I think some brief documentation about writing this custom method is
quite relevant maybe based on already existing comments in the code.

Kind regards,
Pavel

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