Re: Find out the indexed columns

I wrote:
> You could get back the column name(s) by joining to pg_attribute,

Oh, another possible approach is to use pg_describe_object,
which'd be interesting if you also want to handle non-column
dependencies. For example,

regression=# drop table t;
DROP TABLE
regression=# create table t(f1 text);
CREATE TABLE
regression=# create index ti on t (fipshash(f1));
CREATE INDEX
regression=# select * from pg_depend where classid = 'pg_class'::regclass and objid = 'ti'::regclass;
classid | objid | objsubid | refclassid | refobjid | refobjsubid | deptype
---------+-------+----------+------------+----------+-------------+---------
1259 | 48632 | 0 | 1259 | 48627 | 0 | a
1259 | 48632 | 0 | 1259 | 48627 | 1 | a
1259 | 48632 | 0 | 1255 | 16501 | 0 | n
(3 rows)

regression=# select pg_describe_object(refclassid, refobjid, refobjsubid) from pg_depend where classid = 'pg_class'::regclass and objid = 'ti'::regclass;
pg_describe_object
-------------------------
table t
column f1 of table t
function fipshash(text)
(3 rows)

regards, tom lane