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Re: LMDB concurrent operation and MDB_NOSYNC

Kristian Amlie wrote:

On 03/05/14 17:20, Howard Chu wrote:

Kristian Amlie wrote:

Hi,

Does using MDB_NOSYNC when opening the MDB environment in any way affect
LMDB's ability to do concurrent database access?


No. Why on earth would it? Do you really believe such a crippling flaw
in usability as that would go undocumented?


I do not. :-)

But I had a reproducible crash that would trigger quite easily (within
seconds, most of the time) when trying to write concurrently to an LMDB
database. However, having seen your reply I went deeper to find out how
this could be.

It turns out that LMDB does not work correctly on the AUFS filesystem.
Is this known?
No, thanks for that info. The filesystem types we tested are listed here http://symas.com/mdb/microbench/july/#sec11 

My AUFS version is not the latest, so it's possible it has already been
fixed upstream. Unless you know the state of this already, I'll try to
find out more.

Regards
Kristian Amlie
CFEngine




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