[Info-ingres] 4k Cache

[Steve]

On Thursday, 9 July 2020 18:49:06 UTC+10, Roy Hann  wrote:
> Steve wrote:
> 
> > Recently the 4k DMF cache was enabled across our Ingres environments.
> > 
> > I notice in CBF, for our production environment, the cache type is
> > "shared"  vs in our development environment, where the cache type is
> > "private ( owner=(default) )." The respective lines from the production
> > and development configuration files are shown below:
> > 
> > Production config.dat: 
> > ii.<server>.dbms.private.*.cache.p4k_status: OFF 
> > ii.<server>.dbms.shared.cach_def.cache.p4k_status: ON
> > 
> > Development config.dat: 
> > ii.<myserver>.dbms.private.*.cache.p4k_status: ON
> > 
> > Is the difference due to the fact that production has four DBMS servers
> > vs the single server in development?
> 
> Yep.
> 
> In principle an iidbms server process can serve all your databases. If
> you have more than one server process they need to have a coherent view
> of the cached data, so they need to share the cache.
> 
> Back in the steam age it was claimed--though I doubt it was ever
> experienced by any human user--that having a private cache eliminated
> the need to negotiate for access. Being private was claimed to give a
> performance benefit. (Personally I never saw a system where that would
> have been anywhere near the top of the list of performance drags.
> 
> Roy

Great, thanks Roy. 

Be interested to know what your list of top performance drags are.

Steve