Re: corruption of WAL page header is never reported

On 2021/09/02 16:26, Kyotaro Horiguchi wrote:
> I believe errmsg_buf is an interface to emit error messages dedicated
> to xlogreader that doesn't have an access to elog facility, and
> xlogreader doesn't (or ought not to or expect to) suppose
> non-xlogreader callback functions set the variable. In that sense I
> don't think theoriginally proposed patch is proper for the reason that
> the non-xlogreader callback function may set errmsg_buf. This is what
> I meant by the word "modularity".
>
> For that reason I avoided in my second proposal to call
> XLogReaderValidatePageHeader() at all while not in standby mode,
> because calling the validator function while in non-standby mode
> results in the non-xlogreader function return errmsg_buf. Of course
> we can instead always consume errmsg_buf in the function but I don't
> like to shadow the caller's task.

Understood. Thanks for clarifying this!

> Does that makes sense?

Yes, I'm fine with your latest patch.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION