I have made changes such that backend BDB ( ver 4.5 ) resides in memory instead of on disk . This is with default slapd configuration.
I was hoping to have a better performance with this. But what I now see is that do_add  takes much more time then what it use to take when BDB was on-Disk. Indexing is done on objectclass in both the cases.

Any pointers on why this could be an issue?