Re: pgsql: libpq: Notice errors a backend may have sent just before dying.

On Fri, Nov 13, 2015 at 1:54 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I wrote:
>> After looking around, I suspect what actually happened in your test
>> was that we kept pumping pqReadData until it realized it was seeing EOF,
>> whereupon it did pqDropConnection(), and guess what that does:
>
>> /* Discard any unread/unsent data */
>> conn->inStart = conn->inCursor = conn->inEnd = 0;
>> conn->outCount = 0;
>
> So after further review, this is a bug I introduced in 210eb9b74:
> the fact that some code paths flushed the buffers and some did not
> was less of an oversight than it appeared. That explains why the
> problem wasn't noticed years ago, because we'd certainly tested
> pqHandleSendFailure and friends before.
>
> I'm inclined to deal with this by adding a "dropInput" boolean flag
> to pqDropConnection(), rather than reverting the centralization of
> that logic altogether.
>
> I'll go clean this up ...

Interesting lesson. Thanks!
--
Michael