On Thu, Feb 20, 2014 at 6:24 AM, Haribabu Kommi
<kommi.haribabu@gmail.com> wrote:
> On Thu, Feb 20, 2014 at 11:38 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> > I want to propose a new feature called "priority table" or "cache
>> > table".
>> > This is same as regular table except the pages of these tables are
>> > having
>> > high priority than normal tables. These tables are very useful, where a
>> > faster query processing on some particular tables is expected.
>>
>> Why exactly does the existing LRU behavior of shared buffers not do
>> what you need?
>
>
> Lets assume a database having 3 tables, which are accessed regularly. The
> user is expecting a faster query results on one table.
> Because of LRU behavior which is not happening some times.
I think this will not be a problem for regularly accessed tables(pages),
as per current algorithm they will get more priority before getting
flushed out of shared buffer cache.
Have you come across any such case where regularly accessed pages
get lower priority than non-regularly accessed pages?
However it might be required for cases where user wants to control
such behaviour and pass such hints through table level option or some
other way to indicate that he wants more priority for certain tables
irrespective
of their usage w.r.t other tables.
Now I think here important thing to find out is how much helpful it is for
users or why do they want to control such behaviour even when Database
already takes care of such thing based on access pattern.
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com