[PATCH] LMDB full patch set

Volker Lendecke Volker.Lendecke at SerNet.DE
Mon Apr 16 12:36:29 UTC 2018

On Fri, Apr 13, 2018 at 07:00:35AM +1200, Andrew Bartlett via samba-technical wrote:
> It seems so, and there isn't much we can do.  If you think about a
> fork() based memory model then cleaning up the internal state will only
> dirty memory anyway.  They don't provide a 'clean up after fork()'
> function, but do strictly require that you not touch an environment
> after a fork(). 

Asked Howard directly about fork handling. His reply contains:

> After discussing this on -devel IRC, I think we could add an
> mdb_env_postfork() call that the child can use to make its copy of
> the env valid. It would have the same restrictions as
> mdb_env_set_mapsize() - there must not be any active txns in the
> parent process at the time of fork - they'd just be memleaks in the
> child. The child must call this immediately, and cannot call any
> other LMDB APIs until this is done. But assuming those conditions
> are met, we can continue to use the existing file descriptors and
> mmaps without needing to tear down and reopen.

Would that help us?


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