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List:       openldap-devel
Subject:    Re: Read lock without a write lock
From:       Howard Chu <hyc () symas ! com>
Date:       2013-11-21 18:06:48
Message-ID: 528E4BB8.4010600 () symas ! com
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Milosz Tanski wrote:
> I saw that LMDB recently added a new flag MDB_NOLOCK. Is there a way
> to keep the reader lock file and but do away with the write lock?
>
> My motivation for doing this to be able to use LMDB from a process
> that forks to share the database. And the application can implement
> it's own write lock (mutex in shm or futex on linux).

What advantage do you gain from using your own write lock?

Note that forking to share the database is explicitly *not* supported.

> This would be preferable to having to do doing something like a
> MDB_NOLOCK with a pthread_rwlock since we could still have parallel
> readers with one writer.




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

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