Re: Reduced power consumption in WAL Writer process

On Fri, Jul 15, 2011 at 2:29 PM, Robert Haas <robertmhaas@gmail.com> wrote:

> If the primary goal here is to reduce power consumption, another option
> would be to keep the regular wake-ups most of the time but have some
> mechanism for putting the process to sleep until wakened when no activity
> happens for a certain period of time - say, 10 cycles. I'm not at all sure
> that's better, but it would be less of a change to the existing behavior.

Now we have them, latches seem the best approach because they (mostly)
avoid heuristics.

This proposal works same or better for async transactions.

The only difference is how bulk write operations are handled. As long
as we wake WALWriter before wal_buffers fills then we'll be good.
Wakeup once per wal buffer is too much. I agree we should measure this
to check how frequently wakeups are required for bulk ops.

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