Re: "another command is already in progress" error (fwd)

pgsql(at)frenzy(dot)org writes:
> I am doing asynchronous sql calls using the postgres C library.
> After doing two PQsendQuery() calls, I get the
> "another command is already in progress" error.
> The two calls I am doing are an update, and then an insert, in that order.
> I am doing this for speed, since my program can't afford to wait for the
> answer from the first to complete before making the request for the
> second.
> For some reason this method has started giving the error above, even
> though it has been running on the same testing box for its entire
> lifecycle and it wasn't before.

I don't think I believe that; that has never been supported.

If you have several commands you'd like to fire off as a batch, you can
put them in a single PQsendQuery (with semicolons between of course).
Then keep reading PGresults until you get a NULL. But you can't issue
another PQsendQuery until you've gotten that NULL.

At least, not on the same connection. I'm not sure opening multiple
connections could be a win for you, but it might be something to think
about.

regards, tom lane