Support for UDFs with RETURNS TABLE

[fulghum]

No description provided.

[github-actions]

	Main	PR
covering_index_scan_postgres	581.91/s	576.10/s	-1.0%
index_join_postgres	118.96/s	119.63/s	+0.5%
index_join_scan_postgres	181.21/s	180.57/s	-0.4%
index_scan_postgres	11.40/s	11.39/s	-0.1%
oltp_point_select	2372.87/s	2295.48/s	-3.3%
oltp_read_only	1718.61/s	1703.70/s	-0.9%
select_random_points	109.33/s	105.62/s	-3.4%
select_random_ranges	429.64/s	436.02/s	+1.4%
table_scan_postgres	11.28/s	11.13/s	-1.4%
types_table_scan_postgres	5.20/s	5.10/s	-2.0%

[github-actions]

	Main	PR
Total	42090	42090
Successful	17565	17567
Failures	24525	24523
Partial Successes1	5583	5582

	Main	PR
Successful	41.7320%	41.7368%
Failures	58.2680%	58.2632%

${\color{red}Regressions (1)}$

rangefuncs

QUERY:          SELECT * FROM rngfunc() GROUP BY 1;
RECEIVED ERROR: expected []RecordValue, but got string (errno 1105) (sqlstate HY000)

${\color{lightgreen}Progressions (2)}$

arrays

QUERY: select unnest(array[1,2,3,4.5]::float8[]);

QUERY: select unnest(array[1,2,3,4.5]::numeric[]);

Footnotes

1. These are tests that we're marking as Successful, however they do not match the expected output in some way. This is due to small differences, such as different wording on the error messages, or the column names being incorrect while the data itself is correct. ↩

[fulghum]

The regression called out is when executing this SQL function:

CREATE OR REPLACE FUNCTION rngfunc()
          RETURNS TABLE(a varchar(5))
          AS $$ SELECT 'hello'::varchar(5) $$ LANGUAGE sql STABLE;

Doltgres was previously executing this without an error, but not correctly – it declares it returns an anonymous composite type composed of one varchar(5) but returns a varchar(5) directly, not a record. This new code correctly recognizes the return type as an anonymous composite, so when the SQL function doesn't return a record, we now get an error.

The follow up fix for this is to look at our SQL function code and have it support returning anonymous composites.

[Hydrocharged]

LGTM!