Re: [Monotone-devel] RFC: do no exit mtn if database is locked

[Thomas Keller]

Nuno Lucas schrieb:
> The functionality you are implementing is already provided by
> sqlite3_busy_timeout(), and handles the case of waiting a fixed time
> (you could get a client "starved" for long periods of time with this
> aproach), as long as sqlite3OsSleep() is implemented  with the
> equivalent of usleep() (which posix and windows OS's do).

I read of that one as well, but I thought of this as being a bit 
unflexible, also because one cannot inform the user that we're actually 
waiting for such a lock (which is the main thing IMHO), as he/she would 
just sit in front of mtn and think "why does this action take so long?!"

> Also, by always retrying, you can get into a deadlock, as explained in
> the documentation you have linked to.

One could solve this by only trying to gather the lock a specific amount 
of tries or allow to ctrl-c before this happens.

> You may want to give a look into the sqliteDefaultBusyCallback()
> implementation (in the sqlite source file main.c), which is the one
> setup by the sqlite3_busy_timeout() function.

Indeed, I could snatch the code right from there =)

Thomas.


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