Horton

Re: Pluggable Storage - Andres's take

Ashwin Agrawal <aagrawal@pivotal.io>

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From: Ashwin Agrawal <aagrawal@pivotal.io>
To: Andres Freund <andres@anarazel.de>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Tom Lane <tgl@sss.pgh.pa.us>, Justin Pryzby <pryzby@telsasoft.com>, Haribabu Kommi <kommi.haribabu@gmail.com>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>, Alvaro Herrera <alvherre@2ndquadrant.com>, David Rowley <david.rowley@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Asim R P <apraveen@pivotal.io>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Dmitry Dolgov <9erthalion6@gmail.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>
Date: 2019-05-17T23:56:04Z
Lists: pgsql-hackers 
On Wed, May 15, 2019 at 11:54 AM Andres Freund <andres@anarazel.de> wrote:

> Attached is a prototype of a variation of this. I added a
> table_tuple_tid_valid(TableScanDesc sscan, ItemPointer tid)
> callback / wrapper. Currently it just takes a "plain" scan, but we could
> add a separate table_beginscan variant too.
>
> For heap that just means we can just use HeapScanDesc's rs_nblock to
> filter out invalid tids, and we only need to call
> RelationGetNumberOfBlocks() once, rather than every
> table_tuple_tid_valid(0 / table_get_latest_tid() call. Which is a good
> improvement for nodeTidscan's table_get_latest_tid() call (for WHERE
> CURRENT OF) - which previously computed the relation size once per
> tuple.
>

Question on the patch, if not too late
Why call table_beginscan() in TidNext() and not in ExecInitTidScan() ?
Seems cleaner to have it in ExecInitTidScan().

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.