Re: SPI/backend equivalent of extended-query Describe(statement)?

On 05/25/18 20:07, Andrew Gierth wrote:
>  >> with writing a ParserSetupHook that's just a thin wrapper around
>  >> parse_variable_parameters ?
> 
> That's what I did in pllua-ng. The tricky bit was in arranging to also
> call check_variable_parameters; I considered skipping that part, but
> that seemed like it could be potentially problematic.
> 
> https://github.com/pllua/pllua-ng/blob/master/src/spi.c#L266
>
>/*
> * GAH. To do parameter type checking properly, we have to install our
> * own global post-parse hook transiently.
> */
>...
>PG_TRY();
>{
>    pllua_spi_prev_parse_hook = post_parse_analyze_hook;
>    post_parse_analyze_hook = pllua_spi_prepare_checkparam_hook;
>...
>PG_CATCH();
>{
>    post_parse_analyze_hook = pllua_spi_prev_parse_hook;
>    --pllua_spi_prepare_recursion;
>    PG_RE_THROW();
>...

Gah, indeed. Thanks for the heads up. I would never have guessed it'd
be that fiddly.

-Chap