Re: query cancel issues in contrib/dblink

On Thu, Jun 25, 2009 at 10:41 PM, Itagaki
Takahiro<itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp> wrote:
> Hi,
>
> contrib/dblink seems to have no treatments for query cancels.
> It causes the following issues:
>
> (1) Users need to wait for completion of remote query.
>    Requests for query cancel won't be delivered to remote servers.
>
> (2) PGresult objects will be memory leak. The result is not released
>    when query is cancelled; it is released only when dblink function
>    is called max_calls times.
>
> They are long standing issues (not only in 8.4),
> but I hope we will fix them to make dblink more robust.
>
> For (1), asynchronous libpq functions should be used instead of blocking
> ones, and wait for the remote query using a loop with CHECK_FOR_INTERRUPTS().

How would you structure this loop exactly?

merlin