Re: Whether the function exists a in pgsql table or not? - Mailing list pgsql-general

From Greg Smith
Subject Re: Whether the function exists a in pgsql table or not?
Date
Msg-id 4E5B00D3.9090904@2ndQuadrant.com
Whole thread Raw
In response to Whether the function exists a in pgsql table or not?  (shuaixf <shuaixf@gmail.com>)
Responses Re: Whether the function exists a in pgsql table or not?  (shuaixf <shuaixf@gmail.com>)
List pgsql-general
On 08/27/2011 01:21 PM, shuaixf wrote:
> In Oracle, when the table has few records, used frequently, it would use
> "storage(buffer_pool keep)" to keep the data in cache instead of LRU
> algorithm.
>
> if the function exists in a pgsql table or not?
>

There aren't any controls to pin a table into memory in PostgreSQL.  The
way the database uses both its dedicated buffer cache as well as the OS
one, it's hard to even define such a UI that would make sense--the
database doesn't have any control or interaction with the OS cache.

The mechanism for deciding what stays in the PostgreSQL cache is a bit
more complicated than an LRU, while the one in the OS probably is a
LRU.  If the table is used frequently, it's very likely to stay in one
of the two caches anyway.

--
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.


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