Is there any mechanism in LMDB to give back disk space after some particular
amount of row deletion, how does this work, if not are there any plans for it
No. LMDB keeps all space and reuses it for future write operations.
If there's not, as a user I need 2x disk space and some mechanism
to be able
to migrate, so automatic shrinking would be a great thing.
There's nothing automatic but you can use mdb_env_copy() to implement your own
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/