Re: logical decoding : exceeded maxAllocatedDescs for .spill files

On Thu, 19 Dec 2019 at 11:59, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Wed, Dec 18, 2019 at 12:34 PM Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com> wrote:
> >
> > On Tue, 17 Dec 2019 at 17:40, Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com> wrote:
> > > By the way, the backport patch is turning out to be simpler. It's
> > > because in pre-12 versions, the file offset is part of the Vfd
> > > structure, so all the offset handling is not required.
> >
> > Please have a look at the attached backport patch for PG 11. branch.
> > Once you are ok with the patch, I will port it on other branches.
> > Note that in the patch, wherever applicable I have renamed the fd
> > variable to vfd to signify that it is a vfd, and not the kernel fd. If
> > we don't do the renaming, the patch would be still smaller, but I
> > think the renaming makes sense.
> >
>
> The other usage of PathNameOpenFile in md.c is already using 'fd' as a
> variable name (also, if you see example in fd.h, that also uses fd as
> variable name), so I don't see any problem with using fd especially if
> that leads to lesser changes.

Ok. I have retained fd name.

> Apart from that, your patch LGTM.
Attached are the patches from master back up to 94 branch.

PG 9.4 and 9.5 have a common patch to be applied :
pg94_95_use_vfd_for_logrep.patch
From PG 9.6 onwards, each version has a separate patch.

For PG 9.6, there is no logical decoding perl test file. So I have
made a new file 006_logical_decoding_spill.pl that has only the
specific testcase. Also, for building the test_decoding.so, I had to
add the EXTRA_INSTALL=contrib/test_decoding line in the
src/test/recovery/Makefile, because this is the first time we are
using the plugin in the 9.6 tap test.

From PG 10 onwards, pgstat_report_*() calls around read() are removed
in the patch, because FileRead() itself reports the wait events.

From PG 12 onwards, the vfd offset handling had to be added, because
the offset is not present in Vfd structure.

In master, logical_decoding_work_mem is used in the test file.

--
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company