I had to duplicate an LMDB database for replication recently, and used mdb_copy to do so. One server is using the original data.mdb database (which is sparse) and the other is using the mdb_copy non-sparse data.mdb file. The two servers are identical (hardware, OS, software and configuration). OpenLDAP-2.4.39 is being used, 64 bit Linux OS. mdb_stat shows the map size as the same, which is expected. Will the use of the non-sparse file cause any performance issues? The reason for asking is that I am seeing a difference in search times between the two. With 20 million objects, a search on modifyTimestamp (which is indexed) gives: server 1: approx 1s server 2: approx 60s server 2 started with the same search time as server 1 when the databases were originally copied, but has slowly increased its search time over about a week for this same search.
