Re: Overlays and OpenLDAP multi-threading model

[masarati@aero.polimi.it]

> Hi!
>
> I'm starting to see how overlays works to write one. But I've got a
> doubt and I'm asking
> to be sure: Is the overlay stack called within each thread ? If so, I
> think it can't block an
> entire thread pool, right ?
>
> My concern is about performance. The overlay I'm writing will only
> take place in some
> backend data modifications but it can be quite slow in terms of
> OpenLDAP connection handling,
> because it will be communicating via IPC with another process... If
> this overlay blocks only one
> connection, it's ok. But if it's blocks an entire thread pool, I'll
> have to figure out another solution.

The overlay stack is called within the execution of an operation.  As
such, it only affects the thread that executes that operation, unless your
code does something nasty like locking global mutexes.  This implies that
it is *not* entirely blocking a connection: a connection can
simultaneously spawn multiple operations.  It is not clear from your
message how your overlay can affect OpenLDAP connection handling, as this
is not usually exposed in overlay handling.

p.