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Re: Possibility of supporting snapshot in LMDB

Xinhai Kang wrote:

I am new to LMDB and I am checking the possibility of having persistent
snapshot support in LMDB.
In the current code, LMDB creates a transient snapshot when a transaction is
started. And also, LMDA supports multiple multiple databases in an
environment. I am wondering if it is possible to make the snapshot persistent
by storing the snapshot as a separate database (can different database share
pages? Or can multiple trees in the same database?).

I look forward to hearing from you! Or please kindly let me know if similar
feature has already been implemented somewhere.

That is not a feature that we need/want in LMDB. If you want persistent access to historical versions of a DB, use an append-only database. The btree.c written by Martin Hedenfalk would be one example.

  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/