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Re: (ITS#7651) LMDB: Uncontrolled database when opened from multiple processes
- To: openldap-its@OpenLDAP.org
- Subject: Re: (ITS#7651) LMDB: Uncontrolled database when opened from multiple processes
- From: firstname.lastname@example.org
- Date: Wed, 31 Jul 2013 16:44:15 GMT
- Auto-submitted: auto-generated (OpenLDAP-ITS)
> I'd call this two doc bugs:
> Something should mention that once a page has been used, the file will
> never shrink below that page. (Can't quite say that the file never
> shrinks, since WRITEMAP and Windows will set it to exact re-configurable
> mapsize in some cases. If I remember correctly.)
You cannot shrink the mapsize below that last used page, and the last used
page is a non-decreasing number.
> mdb_env_copy() and mdb_env_copyfd() should document that
> @node This call can trigger siginficant file size growth if run in
> parallel with write transactions, because it employs a read-only
> transaction. See long-lived transactions under Caveats.
> I wonder that means these functions should have a flag parameter.
> For some databases, users might prefer a _write_ transaction while
> reading the DB, blocking writes while copying.
No one has ever wanted a hot-backup function that halts writes. You might as
well not do a hot-backup at all.
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/