Re: bdb cachesize and idlcachesize

[Dusty Doris <openldap@mail.doris.cc>]

>
>
> --On Tuesday, February 22, 2005 12:15 PM -0500 Dusty Doris
> <openldap@mail.doris.cc> wrote:
>
> > Few questions, if you change the cachesize and idlecachesize entries, do
> > you have to do anything special aside from restarting slapd, such as run
> > slapindex or db_recover?
> >
> > Also, is there any way to tell how much memory these caches are taking up
> > to make sure they are not set too large?  What happens if you set your
> > cachesize too large and you don't have enough available memory to store
> > these?  Will that cause an issue with openldap, or will it just not cache
> > those entries that would make it exceed its available memory.  Will it
> > just use some sort of FIFO on those caches?
>
> It will consume the memory resources of your system, and likely cause
> issues.
>
> > Finally, what do most people try to achieve with these values?  Would the
> > goal be to make these as big as the directory?  So, if I have 400,000 dn's
> > in my directory, would it be safe to set these at 400000 or would
> > something like 20,000 be good enough to get a nice performance increase?
>
> I try to cache the most actively used entries.  Unless you expect all
> 400,000 entries of your DB to be accessed regularly, there is no need to
> cache that many entries.  My entry cache is set to 20,000 (out of a little
> over 400,000 entries).
>
> The idl cache has to do with how many unique result sets of searches you
> want to store in memory.  Setting up this cache will allow your most
> frequently placed searches to get results much faster, but I doubt you want
> to try and cache the results of every search that hits your system. ;)
>
> --Quanah
>

Thanks for the advice, that makes sense.