Re: [RFC, POC] Don't require a NBuffer sized PrivateRefCount array of local buffer pins - Mailing list pgsql-hackers

From Jim Nasby
Subject Re: [RFC, POC] Don't require a NBuffer sized PrivateRefCount array of local buffer pins
Date
Msg-id 53FE1DF9.3030305@nasby.net
Whole thread Raw
In response to Re: [RFC, POC] Don't require a NBuffer sized PrivateRefCount array of local buffer pins  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers
On 8/27/14, 1:38 AM, Andres Freund wrote:
>> It occurs to me that it'd also be nice to have some
>> >stats available on how this is performing; perhaps a dtrace probe for
>> >whenever we overflow to the hash table, and one that shows maximum
>> >usage for a statement? (Presumably that's not much extra code or
>> >overhead...)
> I don't use dtrace, so*I*  won't do that. Personally I just dynamically
> add probes using "perf probe" when I need to track something like this.

Yeah, I didn't mean dtrace directly; don't we have some macro that equates to dtrace or perf-probe depending on
architecture?

> I don't see how you could track maximum usage without more
> compliations/slowdowns than warranted.

I was thinking we'd only show maximum if we overflowed, but maybe it's still too much overhead in that case.

In any case, I was thinking this would be trivial to add now, but if it's not then someone can do it when there's
actualneed.
 
-- 
Jim C. Nasby, Data Architect                       jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net



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