Datastore & backup - request for help

Martin Langhoff martin.langhoff at
Wed May 21 07:37:27 EDT 2008

On Wed, May 21, 2008 at 8:40 PM, Bert Freudenberg <bert at> wrote:
> Yes, hal-* does a D-Bus round-trip. You could get as fast by using HAL only
> to find the actual sysfs path, and subsequently fetching the data directly
> from sysfs:
> hal-get-property --udi $battery --key linux.sysfs_path

Sounds good. The code I have now does "XO fast" and "everyone else,
portably, a bit slower :-) with no penalty for the XO, so good enough
for me.

>> Now, is there a reasonable way to check for whether we are in a school
>> mesh?
> No idea.

No worries, I cannibalised a bit of bash script from olpc-netstatus
that works well for school networks using an active antenna. I'll have
to see how I make it detect school nets based on APs, but that's
something I'll sort out w Wad.

Any idea if someone can lend a hand with the DS issues I mentioned in
my opening post? To recap:

 - Add a "dump all metadata to a file" mechanism in
datastore/ that is fast. It could be one file per
document, that wouldn't bother me in the least. As long as the
resulting format is a JSON dump of a reasonable datastructure, I'm a
happy camper.

 - Sort out the story with pause()/unpause(). The functions in are meant to "support backup", but I think they are
broken. Reading through the implementation, they call stop() on the
backends, which in the case of Xapian, means that the datastore is
dead in the water while paused, and normal usage will fail.


 martin.langhoff at
 martin at -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff - working code first

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