Re: Performance features the 4th

Manfred Spraul wrote:

> Jan Wieck wrote:
>
>>
>> _Vacuum page delay_:
>>
>> Tom Lane's napping during vacuums with another tuning option. I
>> replaced the usleep() call with a PG_DELAY(msec) macro in miscadmin.h,
>> which does use select(2) instead. That should address the possible
>> portability problems.
>
> What about skipping the delay if there are no outstanding disk
> operations? Then vacuum would get the full disk bandwidth if the system
> is idle.

All we could do is to monitor our own recent activity. I doubt that
anything else would be portable. And on a dedicated DB server that is
very close to the truth anyway.

How portable is getrusage()? Could the postmaster issue that frequently
for RUSAGE_CHILDREN and leave the result somewhere in the shared memory
for whoever is concerned?

Jan

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