Re: Non-replayable WAL records through overflows and >MaxAllocSize lengths

On Fri, 8 Jul 2022 at 21:35, David Zhang <david(dot)zhang(at)highgo(dot)ca> wrote:
>
> Hi,
>
> I tried to apply this patch v5 to current master branch but it complains,
> "git apply --check
> v5-0001-Add-protections-in-xlog-record-APIs-against-large.patch
> error: patch failed: src/include/access/xloginsert.h:43
> error: src/include/access/xloginsert.h: patch does not apply"
>
> then I checked it out before the commit
> `b0a55e43299c4ea2a9a8c757f9c26352407d0ccc` and applied this v5 patch.

The attached rebased patchset should work with master @ 2cd2569c and
REL_15_STABLE @ 53df1e28. I've also added a patch that works for PG14
and earlier, which should be correct for all versions that include
commit 2c03216d (that is, all versions back to 9.5).

> 1) both make check and make installcheck passed.
>
> 2) and I can also see this patch v5 prevents the error happens previously,
>
> "postgres=# SELECT pg_logical_emit_message(false, long, long) FROM
> repeat(repeat(' ', 1024), 1024*1023) as l(long);
> ERROR: too much WAL data"
>
> 3) without this v5 patch, the same test will cause the standby crash
> like below, and the standby not be able to boot up after this crash.

Thanks for reviewing.

Kind regards,

Matthias van de Meent