Re: [HACKERS] libpq and SPI

>
> > What is the problem? I'll research a SPI patch.
>
> Check the hackers thread (last month I think) titled "libpq and SPI";
> the problem occurs when one submits a utility statement rather than
> a plannable query via SPI. Apparently what is happening is that the
> backend emits a 'T' message before it invokes the called statement
> and then emits a 'D' message afterwards --- so if the called statement
> causes a 'C' message to come out, libpq gets unhappy. This seems
> to be clearly a violation of the FE/BE protocol to me, so I don't think
> it's libpq's fault.
>
> Reasonable fixes might be to postpone the sending of 'T' till after
> the invoked statement is executed, or to modify the traffic cop so
> that a utility statement invoked from SPI doesn't send 'C'.
>
> I know a little bit about the parts of the backend that communicate with
> the frontend, but nothing about SPI, so I'm not well prepared to solve
> the problem by myself.

Another major problem of SPI on utilities must get fixed
prior.

SPI cannot save a prepared plan for utilities because
copyObject() doesn't handle the utility part of Query. So it
get's NULL and invoking such a saved plan will cause the
backend to crash.

Jan

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