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Sleepycat and hash functions
http://www.openldap.org/faq/index.cgi?file=756 says one can use BDB's
db_dump utility for on-line backups while slapd is running.
However, db_dump's manpage says:
Dumping and reloading Hash databases that use user-defined hash
functions will result in new databases that use the default hash
function. Although using the default hash function may not be optimal
for the new database, it will continue to work correctly.
Have anyone noticed whether or not such backed-up databases are slower
than "original" databases? Since slapd precalculates hashes and uses a
no-op hash function in back-bdb/dbcache.c, I suppose that means all data
are hashed twice - once by slapd and once by Sleepycat.
The manpage continues:
Dumping and reloading Btree databases that use user-defined prefix or
comparison functions will result in new databases that use the default
prefix and comparison functions. In this case, it is quite likely
that the database will be damaged beyond repair permitting neither
record storage or retrieval.
Since db_dump is recommended, I take it back-bdb does not use Btree