Horton

Re: Pluggable Storage - Andres's take

Haribabu Kommi <kommi.haribabu@gmail.com>

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From: Haribabu Kommi <kommi.haribabu@gmail.com>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@2ndquadrant.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-10-29T04:55:49Z
Lists: pgsql-hackers

Attachments

On Mon, Oct 29, 2018 at 7:40 AM Dmitry Dolgov <9erthalion6@gmail.com> wrote:

> > On Fri, 26 Oct 2018 at 13:25, Haribabu Kommi <kommi.haribabu@gmail.com>
> wrote:
> >
> > Here I attached the cumulative patch with all fixes that are shared in
> earlier mails by me.
> > Except fast_default test, rest of test failures are fixed.
>
> Hi,
>
> If I understand correctly, these patches are for the branch
> "pluggable-storage"
> in [1] (at least I couldn't apply them cleanly to "pluggable-zheap"
> branch),
> right?


Yes, the patches attached are for pluggable-storage branch.


> I've tried to experiment a bit with the current status of the patch, and
> accidentally stumbled upon what seems to be an issue - when I run pgbench
> agains it with some significant number of clients and script [2]:
>
>     $ pgbench -T 60 -c 128 -j 64 -f zipfian.sql
>

Thanks for testing the patches.


> I've got for some client an error:
>
>     client 117 aborted in command 5 (SQL) of script 0; ERROR:
> unrecognized heap_update status: 1
>

This error is for the tuple state of HeapTupleInvisible, As per the comments
in heap_lock_tuple, this is possible in ON CONFLICT UPDATE, but because
of reorganizing of the table_lock_tuple out of EvalPlanQual(), the invisible
error is returned in other cases also. This case is missed in the new code.


> This problem couldn't be reproduced on the master branch, so I've tried to
> investigate it. It comes from nodeModifyTable.c:1267, when we've got
> HeapTupleInvisible as a result, and this value in turn comes from
> table_lock_tuple. Everything points to the new way of handling
> HeapTupleUpdated
> result from heap_update, when table_lock_tuple call was introduced. Since I
> don't see anything similar in the master branch, can anyone clarify why is
> this
> lock necessary here?


In the master branch code also, there is a tuple lock that is happening in
EvalPlanQual() function, but pluggable-storage code, the lock is kept
outside
and also function call rearrangements, to make it easier for the table
access
methods to provide their own MVCC implementation.


> Out of curiosity I've rearranged the code, that handles
> HeapTupleUpdated, back to switch and removed table_lock_tuple (see the
> attached
> patch, it can be applied on top of the lastest two patches posted by
> Haribabu)
> and it seems to solve the issue.
>

Thanks for the patch. I didn't reproduce the problem, based on the error
from
your mail, the attached draft patch of handling of invisible tuples in
update and
delete cases should also fix it.

Regards,
Haribabu Kommi
Fujitsu Australia

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.