Oddities with ANYARRAY

David Fetter and I were just looking at something on IRC...

decibel=# select most_common_vals[1] from pg_stats where tablename='pg_depend' and attname='classid';
ERROR: cannot subscript type anyarray because it is not an array
decibel=# select most_common_freqs[1] from pg_stats where tablename='pg_depend' and attname='classid';
most_common_freqs
-------------------
0.566
(1 row)

ISTM you'd want to be able to reference an individual element of an
ANYARRAY... but this gets even more odd...

decibel=# CREATE OR REPLACE FUNCTION array_to_set(anyarray) RETURNS SETOF anyelement LANGUAGE SQL AS $$
SELECT $1[i] from generate_series(array_lower($1, 1), array_upper($1, 1)) i
$$;
CREATE FUNCTION
decibel=# select array_to_set(most_common_vals) from pg_stats where tablename='pg_depend' and attname='classid';
ERROR: argument declared "anyarray" is not an array but type anyarray

I expected that not to work, but the error is somewhat interesting...

I didn't expect the following to work:

decibel=# select array_to_set(most_common_freqs) from pg_stats where tablename='pg_depend' and attname='classid';
array_to_set
--------------
0.566
0.235667
0.126333
0.0343333
0.02
0.0163333
0.000666667
0.000666667
(8 rows)

decibel=#

ISTM you should be able to call an anyarray function with an anyarray,
and that you should be able to reference individual elements of an
anyarray...
--
Decibel!, aka Jim Nasby decibel(at)decibel(dot)org
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)