Re: [HACKERS] WAL logging problem in 9.4.3?

Hello, Noah.

At Wed, 25 Dec 2019 20:22:04 -0800, Noah Misch <noah(at)leadboat(dot)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(at)leadboat(dot)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