Re: Entities created in one query not available in another in extended protocol

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> On 11 June 2015 at 22:12, Shay Rojansky <roji(at)roji(dot)org> wrote:
>> Just in case it's interesting to you... The reason we implemented things
>> this way is in order to avoid a deadlock situation - if we send two queries
>> as P1/D1/B1/E1/P2/D2/B2/E2, and the first query has a large resultset,
>> PostgreSQL may block writing the resultset, since Npgsql isn't reading it
>> at that point. Npgsql on its part may get stuck writing the second query
>> (if it's big enough) since PostgreSQL isn't reading on its end (thanks to
>> Emil Lenngren for pointing this out originally).

> That part does sound like a problem that we have no good answer to. Sounds
> worth starting a new thread on that.

I do not accept that the backend needs to deal with that; it's the
responsibility of the client side to manage buffering properly if it is
trying to overlap sending the next query with receipt of data from a
previous one. See commit 2a3f6e368 for a related issue in libpq.

regards, tom lane