Re: Attempt to consolidate reading of XLOG page

Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:

> I agree that xlog reading is pretty messy.
>
> I think ifdef'ing the way XLogRead reports errors is not great. Maybe
> we can pass a function pointer that is to be called in case of errors?

I'll try a bit harder to evaluate the existing approaches to report the same
error on both backend and frontend side.

> Not sure about the walsize; maybe it can be a member in XLogReadPos, and
> given to XLogReadInitPos()? (Maybe rename XLogReadPos as
> XLogReadContext or something like that, indicating it's not just the
> read position.)

As pointed out by others, XLogReadPos is not necessary. So if XLogRead()
receives XLogReaderState instead, it can get the segment size from there.

Thanks.

--
Antonin Houska
Web: https://www.cybertec-postgresql.com