Horton

Re: Pluggable Storage - Andres's take

Andres Freund <andres@anarazel.de>

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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: 2019-03-09T03:13:10Z
Lists: pgsql-hackers

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Hi,

On 2019-03-05 23:07:21 -0800, Andres Freund wrote:
> My next steps are:
> - final polish & push the basic DDL and pg_dump patches
> - cleanup & polish the ON CONFLICT refactoring

Those are pushed.


> - 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.

I decided not to split it up further, and even merged two small commits
into it. Subdividing it cleanly would have required making some changes
just to undo them in a subsequent patch.


> - improve documentation for the individual callbacks (integrating
>   work done by others on this thread), in the header

I've done that for the callbacks in the above commit.

Changes:
- I've added comments to all the callbacks in the first commit / the
  scan commit
- I've renamed table_gimmegimmeslot to table_slot_create
- I've made the callbacks and their wrappers more consistently named
- I've added asserts for necessary callbacks in scan commit
- Lots of smaller cleanup
- Added a commit message

While 0001 is pretty bulky, the interesting bits concentrate on a
comparatively small area. I'd appreciate if somebody could give the
comments added in tableam.h a read (both on callbacks, and their
wrappers, as they have different audiences). It'd make sense to first
read the commit message, to understand the goal (and I'd obviously also
appreciate suggestions for improvements there as well).

I'm pretty happy with the current state of the scan patch. I plan to do
two more passes through it (formatting, comment polishing, etc. I don't
know of any functional changes needed), and then commit it, lest
somebody objects.

Greetings,

Andres Freund

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.