Re: Priority table or Cache table

On Mon, Mar 17, 2014 at 1:16 PM, Haribabu Kommi
<kommi(dot)haribabu(at)gmail(dot)com> wrote:
> On Fri, Feb 21, 2014 at 12:02 PM, Haribabu Kommi
> <kommi(dot)haribabu(at)gmail(dot)com> wrote:
>> On Thu, Feb 20, 2014 at 10:06 PM, Ashutosh Bapat
>> <ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>>>
>>> On Thu, Feb 20, 2014 at 10:23 AM, Haribabu Kommi
>>> <kommi(dot)haribabu(at)gmail(dot)com> wrote:
>>>>
>>>> On Thu, Feb 20, 2014 at 2:26 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
>>>> wrote:
>>>>>
>>>>> On Thu, Feb 20, 2014 at 6:24 AM, Haribabu Kommi
>>>>> <kommi(dot)haribabu(at)gmail(dot)com> wrote:
>>>>> > On Thu, Feb 20, 2014 at 11:38 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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 Implemented a proof of concept patch to see whether the buffer pool
> split can improve the performance or not.
>
> Summary of the changes:
> 1. The priority buffers are allocated as continuous to the shared buffers.
> 2. Added new reloption parameter called "buffer_pool" to specify the
> buffer_pool user wants the table to use.

I'm not sure if storing the information of "priority table" into
database is good
because this means that it's replicated to the standby and the same table
will be treated with high priority even in the standby server. I can imagine
some users want to set different tables as high priority ones in master and
standby.

Regards,

--
Fujii Masao