The following bug has been logged on the website:
Bug reference: 9817
Logged by: Dmitry Ryabov
Email address: dmitry-ryabov@mail.ru
PostgreSQL version: 9.3.4
Operating system: Any
Description:
-- HOW REPRODUCE:
CREATE TABLE test (
id INTEGER NOT NULL,
value TEXT NOT NULL,
PRIMARY KEY(id)
);
-- just test function
CREATE FUNCTION test_value_func (
text,
variadic text []
)
RETURNS bigint AS
$body$
select sum(position(unnest in $1)) from unnest($2)
$body$
LANGUAGE 'sql'
IMMUTABLE
CALLED ON NULL INPUT
SECURITY INVOKER;
truncate test;
insert into test select generate_series(1, 1000000), md5(random()::text);
CREATE INDEX test_idx ON public.test
USING btree ((test_value_func(value, 'a', 'b')));
-- index scan used
select * from test where test_value_func(value, 'a', 'b') > 60;
DROP INDEX test_idx;
-- but after restore from backup index created like this
CREATE INDEX test_idx ON public.test
USING btree ((test_value_func(value, VARIADIC ARRAY['a'::text,
'b'::text])));
-- BUG! index scan isn't used
select * from test where test_value_func(value, 'a', 'b') > 60;
-- index scan used
select * from test where test_value_func(value, VARIADIC ARRAY['a'::text,
'b'::text])>60
DROP INDEX test_idx;
CREATE INDEX test_idx ON public.test
USING btree ((test_value_func(value, 'a', 'b')));
-- index scan used
select * from test where test_value_func(value, 'a', 'b') > 60;
-- BUG! index scan isn't used
select * from test where test_value_func(value, VARIADIC ARRAY['a'::text,
'b'::text])>60
-- affected version: 9.3.4
-- not affected version: 9.1.13 - index scan used in both cases
DROP TABLE test;
DROP FUNCTION test_value_func(text, variadic text []);