>> > 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?
Because of other regularly accessed tables, some times the table which expects faster results is getting delayed.
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.
Yes it is useful in cases where the application always expects the faster results whether the table is used regularly or not.
