Re: LRU Parameters
David Williams wrote:
>
> In article <01bd6c5b$658ff980$8da4d2cc@scott>, Scott Kolaya
> <skolaya1@nycap.rr.com> writes
> >Values of:
> >
> >LRU_MAX_DIRTY 3
> >LRU_MIN_DIRTY 2> >
> >are commonly used for OLTP processing to decrease the length of a
> >checkpoint. How long are your checkpoints taking? They should be very
> >short with those values, but your write cache will suffer.
> >
> Agreed, some people even go as low as 1 and 2.
Actually some of us go as low as 2 & 0 or 1 & 0 to get checkpoint times
down to a minimum.
By the way: Joao's CLEANERS value is much too low. With 32 LRUs one
should have 32 CLEANERS unless one has > 32 chunks then add more than
32 cleaners. You should have: #Chunks <= #CLEANERS >= #LRUs to
minimize checkpoint times.
Art S. Kagel