Full_Name: Roman Gershman Version: OS: linux 3.8.0-25-generic URL: Submission from: (NULL) (212.150.97.210)
The program writes into mdb database 100 million key,value pairs. All keys are 64bit integers. If we open the new database with mdb_dbi_open(txn, NULL, 0, &dbi); it has excellent performance - writes are done very quickly.
However if we open it with "mdb_dbi_open(txn, NULL, MDB_INTEGERKEY, &dbi)" (and this is the only change in the code) its performance quickly deteriorates and after it writes several million items to the clean db the difference in write times becomes 2 orders of magnitude or even more compared to the previous setting.
We used the source from git repository git://gitorious.org/mdb/mdb.git at commit id 214e9ed07d566307f22e16d0c1f1f57be9504a3b