Re: Use get_call_result_type() more widely

Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> writes:
> A review comment in another thread [1] by Michael Paquier about the
> usage of get_call_result_type() instead of explicit building of
> TupleDesc made me think about using it more widely. Actually, the
> get_call_result_type() looks at the function definitions to figure the
> column names and build the required TupleDesc, usage of which avoids
> duplication of the column names between pg_proc.dat/function
> definitions and source code. Also, it saves a good number of LOC ~415
> [2] and the size of all the object files put together gets reduced by
> ~4MB, which means, the postgres binary becomes leaner by ~4MB [3].

Saving code is nice, but I'd assume the result is slower, because
get_call_result_type has to do a pretty substantial amount of work
to get the data to construct the tupdesc from. Have you tried to
quantify how much overhead this'd add? Which of these functions
can we safely consider to be non-performance-critical?

regards, tom lane