Re: Out of space situation and WAL log pre-allocation (was Tablespaces)

>Joe Conway [mailto:mail(at)joeconway(dot)com]
> Simon Riggs wrote:
> >> Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us] That should be user-scriptable
> >> policy, in my worldview.
>
> > O... and other dbms will freeze when this situation is hit, rather
> > than continue and drop archive logs.]
>
> Been there, done that, don't see how it's any better. I hesitate to be
> real specific here, but let's just say the end result was restore from
> backup :-(
>
> > So, if we had a parameter called Wal_archive_policy that has 3
> > settings: None = no archiving Optimistic = archive, but if for some
> > reason log space runs out then make space by dropping the oldest
> > archive logs Strict = if log space runs out, stop further write
> > transactions from committing, by whatever means, even if this takes
> > down dbms.
>
> That sounds good to me. For the "Optimistic" case, we need to yell
> loudly if we do find ourselves needing to drop segments. For the
> "Strict" case, we just need to be sure it works correctly ;-)

Good.

Yell loudly really needs to happen sometime earlier, which is as Gavin
originally thought something to do with tablespaces.

Strict behaviour is fairly straightforward, you just PANIC!

I'd think we could rename these to
Fail Operational rather than Optimistic
Fail Safe rather than Strict
...the other names were a bit like "I'm right" and "but I'll do yours
too" ;}

Best Regards, Simon Riggs