Horton

Re: [HACKERS] WAL logging problem in 9.4.3?

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

View thread View on postgr.es
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: noah@leadboat.com
Cc: robertmhaas@gmail.com, pgsql-hackers@postgresql.org, 9erthalion6@gmail.com, andrew.dunstan@2ndquadrant.com, hlinnaka@iki.fi, michael@paquier.xyz
Date: 2019-12-26T09:03:21Z
Lists: pgsql-hackers 
Hello, Noah.

At Wed, 25 Dec 2019 20:22:04 -0800, Noah Misch <noah@leadboat.com> wrote in 
> On Thu, Dec 26, 2019 at 12:46:39PM +0900, Kyotaro Horiguchi wrote:
> > At Wed, 25 Dec 2019 16:15:21 -0800, Noah Misch <noah@leadboat.com> wrote in 
> > >   Skip AssertPendingSyncs_RelationCache() at abort, like v24nm did.  Making
> > >   that work no matter what does ereport(ERROR) would be tricky and low-value.
> > 
> > Right about ereport, but I'm not sure remove the whole assertion from abort.
> 
> You may think of a useful assert location that lacks the problems of asserting
> at abort.  For example, I considered asserting in PortalRunMulti() and
> PortalRun(), just after each command, if still in a transaction.

Thanks for the suggestion. I'll consider that

> > > - Reverted most post-v24nm changes to swap_relation_files().  Under
> > >   "-DRELCACHE_FORCE_RELEASE", relcache.c quickly discards the
> > >   rel1->rd_node.relNode update.  Clearing rel2->rd_createSubid is not right if
> > >   we're running CLUSTER for the second time in one transaction.  I used
> > 
> > I don't agree to that. As I think I have mentioned upthread, rel2 is
> > wrongly marked as "new in this tranction" at that time, which hinders
> > the opportunity of removal and such entries wrongly persist for the
> > backend life and causes problems. (That was found by abort-time
> > AssertPendingSyncs_RelationCache()..)
> 
> I can't reproduce rel2's relcache entry wrongly persisting for the life of a
> backend.  If that were happening, I would expect repeating a CLUSTER command N
> times to increase hash_get_num_entries(RelationIdCache) by at least N.  I
> tried that, but hash_get_num_entries(RelationIdCache) did not increase.  In a
> non-assert build, how can I reproduce problems caused by incorrect
> rd_createSubid on rel2?

As wrote in the another mail. I don't see such a problem and agree to
the removal.

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