Re: [Evolution-hackers] mmaping addressbook database

[Not Zed <notzed ximian com>]

There is actually, i saw your question on irc but i couldn't remember why ...

If you don't specify DB_PRIVATE then it causes libdb to setup the database for multiple-process access.  This is much more complex/slower/uses more resources than a private database.


DB_PRIVATE

Specify that the environment will only be accessed by a single process (although that process may be multithreaded). This flag has two effects on the Berkeley DB environment. First, all underlying data structures are allocated from per-process memory instead of from shared memory that is potentially accessible to more than a single process. Second, mutexes are only configured to work between threads.

On Fri, 2005-05-13 at 11:11 +0100, Ross Burton wrote:
> Hi,
>
> Whilst investigating the memory usage of the addressbook I noticed that
> libdb is using malloc() to store pages from the database.  This is
> caused by use of the DB_PRIVATE flag to the env->open call.  Removing
> this flag causes libdb to mmap the database into memory.
>
> Personally I can't see a problem with removing the DB_PRIVATE flag, but
> I'm not exactly a libdb expert.  Is there a good reason not to remove
> this flag?
>
> Ross