Re: [PATCH] Rename pg_switch_xlog to pg_switch_wal

* Peter Eisentraut (peter(dot)eisentraut(at)2ndquadrant(dot)com) wrote:
> On 1/12/17 2:22 PM, Stephen Frost wrote:
> > The point I was making above is that the only reason to not make such
> > changes is if they really are entirely arbitrary, but I don't think
> > we'd even be having this discussion if that was the case or that we'd
> > be split about the question. We already moved forward with the real
> > change here- pg_xlog -> pg_wal, it really astounds me that we're having
> > to argue about what is primairly just clean-up from that change, at
> > least in my view.
>
> I don't agree with the reasoning. The change of the directory name was
> because some people erroneously delete the directory. There is little
> to no risk that people accidentally delete built-in functions. It was
> not agreed that because we rename the directory that all other uses of
> "xlog" have to be removed as well. All those subsequent changes need to
> stand on their own.

The subsequent discussion about what to call the directory lead to a
pretty clear winner that a better name is "wal", which fits in pretty
nicely with things like "wal_level", "wal_sync_method", "wal_log_hints",
section 19.5 of our documentation. Try finding 'xlog' or even
'transaction log' anywhere in our sample postgresql.conf, in fact.

Look at our docs too, we talk about WAL a *great* deal more than we talk
about 'xlog'. Almost all utilization of 'xlog' that I see is due to
some function or program name which was derived from the directory name,
and half of those end up, confusingly, going back and forth between
"WAL" and "transaction log" (the description of pg_receivexlog is a
great example of this).

In the end, while I don't agree that they really need to, it seems
pretty clear to me that these changes can certainly stand on their own.
The only reason they were ever called 'xlog' was because of the
directory name and without that link, there's really no reason to keep
mis-calling these functions 'xlog' *except* this claim that we don't
want to break things, even though we're changing the directory name.

Thanks!

Stephen