[Qgis-developer] Merging of incompatible changes

[Matthias Kuhn]

On Thu, 2012-10-25 at 13:52 +0200, Martin Dobias wrote:

> Yes, with the current design only one thread (iterator) can read
> particular data at the same time.
> 

Thank you for clarification.
In this case +1 from me for breaking the API.

Maybe most plugins can even be fixed with sed? And for others grep can
give a hint where you have missed something.

> 
> This is where I would like to get in future. But as you noted this
> approach needs greater amount of updates in providers:
> - claiming another iterator means establishment of a new connection to
> the resource (file, db/web connection)
> - necessity to keep a pool of connections (to avoid the overhead of
> establishing new connections) and cleaning of the pool when idle to
> save resources
> - make sure that modifications happen only when no iterators are active

> - ...
> But these are really things related just to internals of providers, so
> no API changes will be necessary. In any case, this is not crucial for
> rendering as usually there aren't concurrent requests for data (from
> other parts of QGIS) while rendering - but if they are, they need to
> be solved somehow - hence the locking mechanism.

I'm already looking forward to this.