On 9/20/2004 2:02 AM, Michael Paesold wrote:
>> The bgwriter always flushes the oldest dirty buffers, and every buffer
>> touched (hit or faulted in). The output above doesn't tell you how many
>> buffers are really dirty. But if the system is under load, that is
>> pretty much the same as the distance between those numbers.
Hmmm, I meant to say that the touched buffers are always put at the
other end of the queue. Jetlag must have swallowed that.
>
> That would be nice, since analysing ARC/bgwriter using the logs would be
> much easier, if it really wrote those in constant intervals independent of
> backend activity.
>
>> > bgwriter_delay = 50 (now default 200)
>> > bgwriter_percent = 2 (now default 1)
>> > bgwriter_maxpages = 200 (now default 100)
>>
>> Just what I was having the best TPC-C results with.
>
> And how were the default values in chosen? Educated guesses?
I am not 100% sure how those came to pass. But certainly not under the
assumption that the default PG install is for a busy server with a
medium to high update rate.
Jan
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