Re: fix "Success" error messages

On Thu, 21 Nov 2019 10:40:36 +0100
Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:

> On 2019-11-21 02:42, TAKATSUKA Haruka wrote:
> > FATAL: could not access status of transaction ..
> > DETAIL: Could not read from file (pg_clog/.... or pg_xact/....) ...: Success.
> >
> > This error has caused the server to fail to start with recovery.
> > I got a report that it happend repeatedly at the newly generated
> > standby cluster. I gave them advice to comfirm the low level server
> > environment.
> >
> > However, in addition to improving the message, should we retry to read
> > the rest of the data in the case reading too few bytes?
> > What about a limited number of retries instead of a complete loop?
>
> If we thought that would help, there are probably hundreds or more other
> places where we read files that would need to be fixed up in the same
> way. That doesn't seem reasonable.
>
> Also, it is my understanding that short reads can in practice only
> happen if the underlying storage is having a serious problem, so
> retrying wouldn't actually help much.

OK, I understand.
In our case, the standby DB cluster space is on DRBD.
I will report the clear occurrence condition if it is found.

thanks,
Haruka Takatsuka