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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