Re: WAL Rate Limiting

Andres Freund <andres@2ndquadrant.com> writes:
> On 2014-01-17 09:04:54 -0500, Robert Haas wrote:
>> That having been said, I bet it could be done at the tail of
>> XLogInsert().

> I don't think there are many locations where this would be ok. Sleeping
> while holding exclusive buffer locks? Quite possibly inside a criticial
> section?

More or less by definition, you're always doing both when you call
XLogInsert.

> Surely not.

I agree.  It's got to be somewhere further up the call stack.

I'm inclined to think that what we ought to do is reconceptualize
vacuum_delay_point() as something a bit more generic, and sprinkle
calls to it in a few more places than now.

It's also interesting to wonder about the relationship to
CHECK_FOR_INTERRUPTS --- although I think that currently, we assume
that that's *cheap* (1 test and branch) as long as nothing is pending.
I don't want to see a bunch of arithmetic added to it.
        regards, tom lane