Horton

Re: Pluggable Storage - Andres's take

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Andres Freund <andres@anarazel.de>, Haribabu Kommi <kommi.haribabu@gmail.com>
Cc: 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: 2019-02-27T10:00:12Z
Lists: pgsql-hackers 
I haven't been following this thread closely, but I looked briefly at 
some of the patches posted here:

On 21/01/2019 11:01, Andres Freund wrote:
> The patchset is now pretty granularly split into individual pieces.

Wow, 42 patches, very granular indeed! That's nice for reviewing, but 
are you planning to squash them before committing? Seems a bit excessive 
for the git history.

Patches 1-4:

* v12-0001-WIP-Introduce-access-table.h-access-relation.h.patch
* v12-0002-Replace-heapam.h-includes-with-relation.h-table..patch
* v12-0003-Replace-uses-of-heap_open-et-al-with-table_open-.patch
* v12-0004-Remove-superfluous-tqual.h-includes.patch

These look good to me. I think it would make sense to squash these 
together, and commit now.


Patches 20 and 21:
* v12-0020-WIP-Slotified-triggers.patch
* v12-0021-WIP-Slotify-EPQ.patch

I like this slotification of trigger and EPQ code. It seems like a nice 
thing to do, independently of the other patches. You said you wanted to 
polish that up to committable state, and commit separately: +1 on that. 
Perhaps do that even before patches 1-4.

> --- a/src/include/commands/trigger.h
> +++ b/src/include/commands/trigger.h
> @@ -35,8 +35,8 @@ typedef struct TriggerData
>  	HeapTuple	tg_trigtuple;
>  	HeapTuple	tg_newtuple;
>  	Trigger    *tg_trigger;
> -	Buffer		tg_trigtuplebuf;
> -	Buffer		tg_newtuplebuf;
> +	TupleTableSlot *tg_trigslot;
> +	TupleTableSlot *tg_newslot;
>  	Tuplestorestate *tg_oldtable;
>  	Tuplestorestate *tg_newtable;
>  } TriggerData;

Do we still need tg_trigtuple and tg_newtuple? Can't we always use the 
corresponding slots instead? Is it for backwards-compatibility with 
user-defined triggers written in C? (Documentation also needs to be 
updated for the changes in this struct)


I didn't look a the rest of the patches yet...

- Heikki

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.