Re: BUG #5716: Regression joining tables in UPDATE with composite types

"Andrew Tipton" <andrew@adioso.com> writes:
> Attempting to execute an UPDATE that joins to another table where the join
> condition is comparing a composite type fails with the (presumably internal)
> error message "psql:testcase.sql:29: ERROR:  could not find pathkey item to
> sort".

Fixed, thanks for the report!

BTW ... while this is unrelated to the cause of the problem, I think
this is quite an inefficient coding technique:

> CREATE TYPE price_key AS (
>     id INTEGER
> );

> CREATE FUNCTION price_key_from_table(price) RETURNS price_key AS $$
>     SELECT $1.id
> $$ LANGUAGE SQL IMMUTABLE;

> CREATE FUNCTION price_key_from_input(price_input) RETURNS price_key AS $$
>     SELECT $1.id
> $$ LANGUAGE SQL IMMUTABLE;

> UPDATE price ...
>     WHERE price_key_from_table(price.*) = price_key_from_input(input_prices.*);

Comparing composite types is probably a good two orders of magnitude
slower than comparing plain ints would be.  I'm sure that coding
technique looks cute, but you're paying through the nose for it.
Consider making price_key a simple domain over int.

            regards, tom lane