Re: WAL Rate Limiting

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().  if there are cases where that's not desirable, then add
> macros HOLDOFF_WAL_THROTTLING() and RESUME_WAL_THROTTLING() that bump
> a counter up and down.  When the counter is >0, XLogInsert() doesn't
> sleep; when RESUME_WAL_THROTTLING() drops the counter to 0, it also
> considers sleeping.  I suspect only a few places would need to do
> this, like where we're holding one of the SLRU locks.

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?
Surely not.

Greetings,

Andres Freund

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