Re: [leafnode-list] lockfiles revisited

[Matthias Andree <ma@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Joerg Dietrich <joerg@xxxxxxxxxxxx> writes:

> Overviews are not locked. It is probably silently assumed that if
> two processes mess an .overview file up, the next call to
> getxover() will repair it. Maybe one should consider writing an
> fcntl() wrapper that takes abritrary filenames as arguments and
> locks or releases these files. Once my exams are over...

What will that help? It will totally spoil performance, since if you're
doing it seriously, you need to obtain the exclusive lock before reading
the overview, you cannot cache it. Record locking might be a way out,
but I'm not sure how portable THAT is, and it would require somewhat
fixed-length records. OTOH, one might try SleepCat DB (a concurrent
write access version), however, I'm not sure how stable these are and if
license conditions would suit leafnode's needs.

-- 
Matthias Andree

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