Re: How does PG know if data is in memory?

2010/10/13 Ron Mayer <rm_pg@cheapcomplexdevices.com>:
> Kevin Grittner wrote:
>>
>> ...Sybase named caches...segment off portions of the memory for
>> specific caches... bind specific database
>> objects (tables and indexes) to specific caches. ...
>>
>> When I posted to the list about it, the response was that LRU
>> eviction was superior to any tuning any human would do.  I didn't
>> and don't believe that....
>>
>> FWIW, the four main reasons for using it were:
>> (1) Heavily used data could be kept fully cached in RAM...
>
> Lightly-used-but-important data seems like another use case.
>
> LRU's probably far better than me at optimizing for the total
> throughput and/or average response time.  But if there's a
> requirement:
>  "Even though this query's very rare, it should respond
>  ASAP, even at the expense of the throughput of the rest
>  of the system."
> it sounds like this kind of hand-tuning might be useful.

it is exactly one of the purpose of pgfincore :
http://villemain.org/projects/pgfincore#load_a_table_or_an_index_in_os_page_cache


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Cédric Villemain               2ndQuadrant
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