Geoff Swan wrote:
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.
If you specified no special options, the file produced by mdb_copy is identical to the original - it will also be sparse if the original is.
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?
Question is irrelevant since both are sparse files.
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.
Look at disk I/O and memory usage, the LMDB file itself has no bearing here.