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Re: how to set entry cache
Is there a way to measure cache (as in idlcachesize and cachesize -- not
the BDB cache) hits, misses, etc?
On Wed, 2005-04-27 at 20:32 -0700, Quanah Gibson-Mount wrote:
> --On Thursday, April 28, 2005 11:13 AM +0800 çåå
> <firstname.lastname@example.org> wrote:
> > but "how to work out what works best for your system"
> > if I have import 10k entry data to bdb,then
> > dn2id.bdb+id2entry.bdb=500MB,Can I think a entry = 500/10000 MB??
> > "idlcachesize Specify the size of the in-memory index cache, in index
> > slots."what is index slots? if I have 10k entry,and config
> > index objectClass eq
> > index cn,sn pres,eq,sub
> > then the max index slots is 10k*3 or 10k or 3?and how to work out how
> > large is one index slots?
> "cachesize" specifies how many entries to cache in system memory, and it
> caches the entries that are most frequently accessed. The amount of
> entries that can be cached is going to be limited by your available memory.
> The size of the *.bdb file has nothing to do with how large an entry cache
> you should set. As I said, you are going to have to experiment.
> "idlcachesize" specifies how many result sets from completed queries to
> cache in system memory, and it caches the most frequently returned result
> sets. The amount of result sets that can be cached is going to be limited
> by your available memory. As I said, you are going to have to experiment.
> A general rule of thumb is to set idlcachesize to 3 * the size of the
> cachesize, but that is not also sufficient.
> Basically, these two settings are things *you* have to experiment with to
> find the correct settings for for your systems, because they are limited in
> scope by the amount of available memory you have. As far as cachesize is
> concerned, being able to cache your entire DB in memory will always be a
> performance boost, but only if you have enough memory available to do that.
> The larger the idlcachesize you can support is probably the better as well.
> Quanah Gibson-Mount
> Principal Software Developer
> ITSS/Shared Services
> Stanford University
> GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html
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Matthew J. Smith
University of Connecticut ITS
This message sent at Thu Apr 28 08:27:11 2005
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