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db_stat and back-bdb index question
http://www.openldap.org/faq/data/cache/1075.html contains the paragraph
"Unlike the B-trees, where you only need to touch one data page to find an entry
of interest, doing an index lookup generally touches multiple keys, and the
point of a hash structure is that the keys are evenly distributed across the
data space. That means there's no convenient compact subset of the database
that you can keep in the cache to insure quick operation, you can pretty much
expect references to be scattered across the whole thing. My strategy here
would be to provide enough cache for at least 50% of all of the hash data.
(Number of hash buckets + number of overflow pages + number of duplicate pages)
* page size / 2."
Now I'm trying to match the phrases in that formulat to the output of db_stat -d
(?) resulting from looking at an index file.
Number of hash buckets = "Number of tree internal pages."
Numer of overflow pages = "Number of tree overflow pages."
Number of duplicate pages = "Number of tree duplicate pages."
Page Size = "Underlying database page size."
- correct? Or should I use some other parametet to db_stat when looking at
these indexes (back-bdb)?
Is this information correct for back-hdb as well?
Adam Tauno Williams
Network & Systems Administrator
Grand Rapids, Mi. USA