3 ms·
Note that if your updates are much smaller than a page, you're gonna have a bad time with LMDB. Optimizations like WAL and group commit exist for a reason.
by senderista 3y ago
Note that if your updates are much smaller than a page, you're gonna have a bad time with LMDB. Optimizations like WAL and group commit exist for a reason.
- lichtenberger 3y agoBecause it has to copy and write entire pages instead of only force a flush of log records due to a WAL?
- lichtenberger 3y agoOh, seems also because of random in-place writes of the B-tree.
- hyc_symas 3y agoFor a 4KB pagesize, the breakeven point in write amplification vs WALs is around 768 bytes. http://www.lmdb.tech/bench/ondisk/ http://www.lmdb.tech/bench/ondisk/ Above that record size, LMDB is more efficient. For OpenLDAP, with LDAP entries typically being at least 1KB, the LMDB design is ideal. If it's not ideal for other applications, oh well.