im.pidgin.pidgin: fdee6fd343192e04665c9e56ceca3ac78f169666

[Ethan Blanton]

Kevin Stange spake unto us the following wisdom:
> Ethan Blanton wrote:
> > I am not at *all* sure that using the journal as a lockfile is safe.
> > (It may be, I am not saying it certainly is not.)  270 seconds is a
> > reasonably conservative pull timeout.
> 
> From my investigation, monotone does the whole pull as a SQL transaction
> and finishes with a commit, so the transaction seems to be entirely
> contained within the journal until the commit is issued -- no mtime
> change for the main DB file until after that.

My understanding from the monotone mailing list and IRC is that
netsyncs are checkpointed from time to time, so that if a pull is
aborted partway through, it does not (always) have to be restarted
from the beginning.  I believe there are triggers on both number of
revisions and total amount of data transferred, though I am not sure.

The important data point, though, is that whether or not this
correlates with the presence of a journal file is dependent on
sqlite's internal operation, and not something we should depend on.

Is there a reason that /usr/bin/lockfile is not appropriate?

Ethan

-- 
The laws that forbid the carrying of arms are laws [that have no remedy
for evils].  They disarm only those who are neither inclined nor
determined to commit crimes.
		-- Cesare Beccaria, "On Crimes and Punishments", 1764
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