Re: [Help-smalltalk] Postgres and blocked poll

[Paolo Bonzini]

On 04/21/2011 12:15 PM, Holger Hans Peter Freyther wrote:
> Hi Paolo,
>
> I have one more issue with the Postgres DBI driver. In case of the VPN
> vanishing (or suspend/resume my laptop) the next database query will call
> PQgetResult which will block in poll forever.
>
> According to the Postgres documentation one can get the socket from the
> connection, use the PQconsumeInput to make PQ read it and there is something
> like PQisbusy.
>
> Now the question is how to integrate this. Whenever executing a query I could
> greate a FileDescriptor, wait until it is readable, call PQconsumeInput..
>
> [
>     PQisBusy..
> ] whileFalse: [
>     (FileDescriptor on: connection socket) ensureReadable.
>     PQConsumeInput..
> ].
>
> Does this sound okay?

Yes, it does, though it should be a SocketImpl, not a FileDescriptor. 
Also, you need to make it non-finalized, or alternatively you can store 
it in an instance variable (preferred, probably).  That would be

...
   socket := Sockets.SocketImpl on: connection pqSocket
...
   [
       socket ensureReadable.
       connection consumeInput; isBusy
   ] whileTrue

Nice API! :)

Paolo