Re: Clock sweep not caching enough B-Tree leaf pages? - Mailing list pgsql-hackers

From David G Johnston
Subject Re: Clock sweep not caching enough B-Tree leaf pages?
Date
Msg-id 1398121636361-5800988.post@n5.nabble.com
Whole thread Raw
In response to Re: Clock sweep not caching enough B-Tree leaf pages?  (Jim Nasby <jim@nasby.net>)
Responses Re: Clock sweep not caching enough B-Tree leaf pages?
Re: Clock sweep not caching enough B-Tree leaf pages?
List pgsql-hackers
Jim Nasby-2 wrote
>> I feel that if there is no memory pressure, frankly it doesnt matter much
>> about what gets out and what not. The case I am specifically targeting is
>> when the clocksweep gets to move about a lot i.e. high memory pressure
>> workloads. Of course,  I may be totally wrong here.
> 
> Well, there's either memory pressure or there isn't. If there isn't then
> it's all moot *because we're not evicting anything*.

The trade-off I'm seeing here is between measuring when there is no memory
pressure - and thus eating at performance while not actually evicting
buffers - and not measuring but then encountering memory pressure and not
having a clue as to what should be evicted.

David J.






--
View this message in context:
http://postgresql.1045698.n5.nabble.com/Clock-sweep-not-caching-enough-B-Tree-leaf-pages-tp5799947p5800988.html
Sent from the PostgreSQL - hackers mailing list archive at Nabble.com.



pgsql-hackers by date:

Previous
From: Jim Nasby
Date:
Subject: Re: Clock sweep not caching enough B-Tree leaf pages?
Next
From: Claudio Freire
Date:
Subject: Re: Clock sweep not caching enough B-Tree leaf pages?