Postgres materialized view hides some data - postgresql

Question

First of all, I can not recreate this example in SQL fiddle, I got some error when I try select from view.
Problem:
I have a materialized view which fetches function parameters from my schema, based on information_schema. When I create it, it works just fine. When I refresh it, it works just fine. When I assign it to some role, and then refresh it - it loses about 75% of its contents, and refreshing does not work. Only thing that works is dropping and re creating the whole view.
Examples:
All examples was executed as superuser. Lets say that I have role:
CREATE ROLE table_owner NOSUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION;
And I have materialized view like this:
CREATE MATERIALIZED VIEW function_def AS
SELECT
regexp_replace(r.specific_name::text, '^(.*)_[0-9]+$'::text, '\1'::text) AS function_name,
r.data_type AS output_type,
r.type_udt_name AS output_udt_name,
p.ordinal_position,
p.parameter_name,
p.data_type,
p.udt_schema,
regexp_replace(p.udt_name::text, '^_'::text, ''::text) AS udt_name
FROM information_schema.routines r
LEFT JOIN information_schema.parameters p ON p.specific_name::text = r.specific_name::text
WHERE 1 = 1 AND p.specific_schema::text = 'mySchema'::text
ORDER BY regexp_replace(r.specific_name::text, '^(.*)_[0-9]+$'::text, '\1'::text), p.ordinal_position
WITH DATA;
CREATE INDEX i_function_def_function_name ON function_def(function_name);
And lets say that in this point statement:
SElECT count(*) FROM function_def
returns 231 rows, which is correct number. Then I assign the ownership of view to some role:
ALTER TABLE function_def OWNER TO table_owner;
and select still returns 231 rows, which is correct number.
SElECT count(*) FROM function_def;
but when I refresh view like this:
REFRESH MATERIALIZED VIEW function_def WITH DATA;
and then:
SElECT count(*) FROM function_def;
the returned number of rows is constant 54, which is not correct.
I am quite puzzled here and would appreciate some help, or hint. Is this a postgres bug, or am I doing something wrong?
EDIT - solution:
As stated by Klin it is in fact a privilege issue! Because all my functions are owned by function_owner, this code has done the trick, and now everything is fine:
ALTER TABLE function_def OWNER TO function_owner;
GRANT SELECT ON TABLE function_def TO GROUP table_owner;

Answer 1

REFRESH MATERIALIZED VIEW is executed with the privileges of the view owner, i.e. table_owner in this case.
The user have no access to some functions and therefore he does not see some records in information_schema.routines.
You can check what functions are not accessible by table_owner by executing this query as superuser:
SELECT
regexp_replace(r.specific_name::text, '^(.*)_[0-9]+$'::text, '\1'::text) AS function_name,
r.data_type AS output_type,
r.type_udt_name AS output_udt_name,
p.ordinal_position,
p.parameter_name,
p.data_type,
p.udt_schema,
regexp_replace(p.udt_name::text, '^_'::text, ''::text) AS udt_name
FROM information_schema.routines r
LEFT JOIN information_schema.parameters p ON p.specific_name::text = r.specific_name::text
WHERE 1 = 1 AND p.specific_schema::text = 'mySchema'::text
EXCEPT
SELECT * FROM function_def;