Horton

Re: WAL logging problem in 9.4.3?

Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>

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From: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
To: michael.paquier@gmail.com
Cc: david@pgmasters.net, hlinnaka@iki.fi, alvherre@2ndquadrant.com, simon@2ndquadrant.com, tgl@sss.pgh.pa.us, andres@anarazel.de, masao.fujii@gmail.com, kleptog@svana.org, pgsql-hackers@postgresql.org
Date: 2016-11-01T02:00:46Z
Lists: pgsql-hackers 
Hi,

At Sun, 2 Oct 2016 21:43:46 +0900, Michael Paquier <michael.paquier@gmail.com> wrote in <CAB7nPqTKOyHkrBSxvvSBZCXvU9F8OT_uumXmST_awKsswQA5Sg@mail.gmail.com>
> On Thu, Sep 29, 2016 at 10:02 PM, Kyotaro HORIGUCHI
> <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> > Hello,
> >
> > At Thu, 29 Sep 2016 16:59:55 +0900, Michael Paquier <michael.paquier@gmail.com> wrote in <CAB7nPqT5x05tG7aut1yz+WJN76DqNz1Jzq46fSFtee4YbY0YcA@mail.gmail.com>
> >> On Mon, Sep 26, 2016 at 5:03 PM, Kyotaro HORIGUCHI
> >> <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> >> > Hello, I return to this before my things:)
> >> >
> >> > Though I haven't played with the patch yet..
> >>
> >> Be sure to run the test cases in the patch or base your tests on them then!
> >
> > All items of 006_truncate_opt fail on ed0b228 and they are fixed
> > with the patch.
> >
> >> > Though I don't know how it actually impacts the perfomance, it
> >> > seems to me that we can live with truncated_to and sync_above in
> >> > RelationData and BufferNeedsWAL(rel, buf) instead of
> >> > HeapNeedsWAL(rel, buf).  Anyway up to one entry for one relation
> >> > seems to exist at once in the hash.
> >>
> >> TBH, I still think that the design of this patch as proposed is pretty
> >> cool and easy to follow.
> >
> > It is clean from certain viewpoint but additional hash,
> > especially hash-searching on every HeapNeedsWAL seems to me to be
> > unacceptable. Do you see it accetable?
> >
> >
> > The attached patch is quiiiccck-and-dirty-hack of Michael's patch
> > just as a PoC of my proposal quoted above. This also passes the
> > 006 test.  The major changes are the following.
> >
> > - Moved sync_above and truncted_to into  RelationData.
> >
> > - Cleaning up is done in AtEOXact_cleanup instead of explicit
> >   calling to smgrDoPendingSyncs().
> >
> > * BufferNeedsWAL (replace of HeapNeedsWAL) no longer requires
> >   hash_search. It just refers to the additional members in the
> >   given Relation.
> >
> > X I feel that I have dropped one of the features of the origitnal
> >   patch during the hack, but I don't recall it clearly now:(
> >
> > X I haven't consider relfilenode replacement, which didn't matter
> >   for the original patch. (but there's few places to consider).
> >
> > What do you think about this?
> 
> I have moved this patch to next CF. (I still need to look at your patch.)

Thanks for considering that.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

Commits

  1. Add perl2host call missing from a new test file.

  2. Skip WAL for new relfilenodes, under wal_level=minimal.

  3. Revert "Skip WAL for new relfilenodes, under wal_level=minimal."

  4. Back-patch log_newpage_range().

  5. During heap rebuild, lock any TOAST index until end of transaction.

  6. In log_newpage_range(), heed forkNum and page_std arguments.

  7. Back-patch src/test/recovery and PostgresNode from 9.6 to 9.5.

  8. Reduce pg_ctl's reaction time when waiting for postmaster start/stop.

  9. Accelerate end-of-transaction dropping of relations

  10. Redesign the planner's handling of index-descent cost estimation.

  11. Make TRUNCATE do truncate-in-place when processing a relation that was created