Re: SQL Function Slowness, 8.3.0

"Gavin M. Roy" <gmr(at)myyearbook(dot)com> writes:
> After detailed examination of pg_stat_user_indexes usage, it's clear that
> the functions don't use the same indexes. I've casted everything to match
> the indexes in the SQL function, to no success. Any suggestions on next
> steps? Maybe for 8.4 we could find a way to explain analyze function
> internals ;-)

Yeah, this could be easier, but it's certainly possible to examine the
plan generated for a function's parameterized statement. For instance,
say you're wondering about the plan for

create function foo(int, text) ... as
$$ select * from bar where f1 = $1 and f2 = $2 $$
language sql

What you do is

prepare p(int, text) as select * from bar where f1 = $1 and f2 = $2 ;

explain analyze execute p(42, 'hello world');

It works exactly the same for statements in plpgsql functions,
remembering that both parameters and local variables of the function
have to become $n placeholders. Remember to make the parameters
of the prepared statement have the same declared types as the
function's parameters and variables.

regards, tom lane