Jürgen Baier wrote: > Hi, > > I'm using LMDB for mapping MD5 hash codes to some data. I noticed that a > virtualized environment (Xen/Windows on our own servers and AWS/Windows) > slows down > LMDB significantly (e.g. a certain workload is executed in 30 minutes on a > local machine vs. 15 hours on AWS).
Sounds like whatever filesystem is running on AWS has a really poor implementation of mmap. > > My application also has an implementation in SQLite which is slower than LMDB > on a local machine. But its performance is similar on AWS. The rough numbers > are > something like > > Local: > > - LMDB: 30 minutes > - SQLite: 45 minutes > > AWS: > > - LMDB: 15 hours > - SQLite: 50 minutes > > I wanted to ask if there is something I can do to speed up LMDB on AWS? Maybe > I'm missing something obvious. Are reads slow, or writes? Or both? If writes are slow, try setting MDB_NOSYNC. If reads are slow,\ use a different filesystem. > > Thanks, > > Jürgen > -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/
