Re: Just-in-time Background Writer Patch+Test Results

On Tue, 25 Sep 2007, Tom Lane wrote:

>> -Heikki didn't like the way I pass information back from SyncOneBuffer
>> back to the background writer.
> I didn't either --- it was too complicated and not actually doing
> anything useful.

I suspect someone (possibly me) may want to put back some of that same
additional complication in the future, but I'm fine with it not being
there yet. The main thing I wanted accomplished was changing the return
to a bitmask of some sort and that's there now; adding more data to that
interface later is at least easier now.

> Also, I set the default value of bgwriter_lru_multiplier to 2.0,
> as 1.0 seemed to be leaving too many writes to the backends in my
> testing.

The data I've collected since originally submitting the patch agrees that
2.0 is probably a better default as well.

I should have time to take an initial stab this week at updating the
documentation to reflect what's now been commited, and to see how this
stacks on top of HOT running pgbench on my test system.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD