Re: archive wal's failure and load increase.

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> We discussed putting PreallocXlogFiles() in bgwriter once before, but I
> think last time we discussed that idea it was rejected, IIRC.

We already do that: it's called a checkpoint.  If the rate of WAL
generation was more than checkpoint_segments per checkpoint_timeout,
then indeed there would be a problem with foreground processes having to
manufacture WAL segment files for themselves, but it would be a bursty
thing (ie, problem goes away after a checkpoint, then comes back).

It's a good thought but I don't think the theory holds water for
explaining Cedric's problem, unless there was *also* some effect
preventing checkpoints from completing ... which would be a much more
serious problem than the archiver failing.

			regards, tom lane