Horton

Re: Pluggable Storage - Andres's take

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Haribabu Kommi <kommi.haribabu@gmail.com>, Asim R P <apraveen@pivotal.io>, Pg Hackers <pgsql-hackers@postgresql.org>, aagrawal@pivotal.io, Dmitry Dolgov <9erthalion6@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>
Date: 2019-03-06T07:07:21Z
Lists: pgsql-hackers

Attachments

Hi,

On 2019-02-27 09:29:31 -0800, Andres Freund wrote:
> Once the EPQ patch (and two other simple preliminary ones) is pushed, I
> plan to post a new rebased version to this thread. That's then really
> only the core table AM work.

That's now done.  Here's my current submission of remaining
patches. I've polished the first patch, adding DDL support, quite a bit,
I'm planning to push that soon.

Changes:

- I've removed the ability to specify a table AM to partitioned tables,
  as discussed at [1]
- That happily shook out a number of bugs, where the partitioned table's
  AM was used, when the leaf partitioned AM should have been used (via
  the slot). In particular this necessicated refactoring the way slots
  are used for ON CONFLICT of partitioned tables. That's the new WIP
  patch in the series. But I think the result is actually clearer.
- I've integrated the pg_dump and psql patches, although I'd made
  HIDE_TABLEAM independent of whether \d+ table is on a table with the
  default AM or not.
- There's a good number of new tests in both the DDL and the pg_dump
  patch
- Lots of smaller cleanups


My next steps are:
- final polish & push the basic DDL and pg_dump patches
- cleanup & polish the ON CONFLICT refactoring
- cleanup & polish the patch adding the tableam based scan
  interface. That's by far the largest patch in the series. I might try
  to split it up further, but it's probably not worth it.
- improve documentation for the individual callbacks (integrating
  work done by others on this thread), in the header
- integrate docs patch
- integrate the revised version of the xid horizon patch by Amit
  Khandekar (reviewed by Robert Haas)
- fix naive implementation of slot based COPY, to not constantly
  drop/recreate slots upon partition change. I've hackplemented a better
  approach, which makes it faster than the current code in my testing.

Notes:
- I'm currently not targeting v13 with "tableam: Fetch tuples for
  triggers & EPQ using a proper snapshot.". While we need something like
  that for some AMs like zheap, I think it's a crap approach and needs
  more thought.

Greetings,

Andres Freund

[1] https://postgr.es/m/20190304234700.w5tmhducs5wxgzls@alap3.anarazel.de

Commits

  1. Add default_table_access_method to postgresql.conf.sample.

  2. tableam: Avoid relying on relation size to determine validity of tids.

  3. tableam: Don't assume that every AM uses md.c style storage.

  4. Allow pg_class xid & multixid horizons to not be set.

  5. Fix slot type issue for fuzzy distance index scan over out-of-core table AM.

  6. tableam: comment and formatting fixes.

  7. table: docs: fix typos and grammar.

  8. tableam: basic documentation.

  9. Only allow heap in a number of contrib modules.

  10. tableam: Add table_finish_bulk_insert().

  11. tableam: sample scan.

  12. tableam: bitmap table scan.

  13. tableam: Move heap specific logic from estimate_rel_size below tableam.

  14. tableam: VACUUM and ANALYZE support.

  15. tableam: relation creation, VACUUM FULL/CLUSTER, SET TABLESPACE.

  16. tableam: Support for an index build's initial table scan(s).

  17. tableam: Add table_get_latest_tid, to wrap heap_get_latest_tid.

  18. tableam: Add helper for indexes to check if a corresponding table tuples exist.

  19. tableam: Add and use table_fetch_row_version().

  20. tableam: Use in CREATE TABLE AS and CREATE MATERIALIZED VIEW.

  21. Ensure sufficient alignment for ParallelTableScanDescData in BTShared.

  22. Don't reuse slots between root and partition in ON CONFLICT ... UPDATE.

  23. Use a virtual rather than a heap slot in two places where that suffices.

  24. Store tuples for EvalPlanQual in slots, rather than as HeapTuples.

  25. Use slots in trigger infrastructure, except for the actual invocation.

  26. Store table oid and tuple's tid in tuple slots directly.

  27. Allow to use HeapTupleData embedded in [Buffer]HeapTupleTableSlot.

  28. Add ExecStorePinnedBufferHeapTuple.

  29. Add ArchiveOpts to pass options to ArchiveEntry

  30. Rename RelationData.rd_amroutine to rd_indam.

  31. Rephrase references to "time qualification".

  32. Move remaining code from tqual.[ch] to heapam.h / heapam_visibility.c.

  33. Move generic snapshot related code from tqual.h to snapmgr.h.

  34. Remove superfluous tqual.h includes.

  35. Don't duplicate parallel seqscan shmem sizing logic in nbtree.

  36. Move vacuumlazy.c into access/heap.

  37. Support parallel bitmap heap scans.