BUG #2848: information_schema.key_column_usage does not work

"Tony Marston" <tony@marston-home.demon.co.uk> writes:

I have the following query:

SELECT key_column_usage.*,constraint_type
FROM information_schema.key_column_usage
LEFT JOIN information_schema.table_constraints USING
(table_schema,table_name,constraint_name)
WHERE table_schema='whatever' and table_name='whatever'
ORDER BY constraint_type, constraint_name, ordinal_position

This works when I am logged on as 'postgres', but if I try it after logging
on with a different username it fails with "ERROR: relation with OID 18635
does not exist".

I tried to reproduce this, but it works for me ...

regards, tom lane

I see the same problem with 8.2 on linux. Laurence

Tony Marston wrote:

Laurence Rowe <l@lrowe.co.uk> writes:

I have the following query:

SELECT key_column_usage.*,constraint_type
FROM information_schema.key_column_usage
LEFT JOIN information_schema.table_constraints USING
(table_schema,table_name,constraint_name)
WHERE table_schema='whatever' and table_name='whatever'
ORDER BY constraint_type, constraint_name, ordinal_position

This works when I am logged on as 'postgres', but if I try it after logging
on with a different username it fails with "ERROR: relation with OID 18635
does not exist".

Hmph ... I recall being unable to reproduce this before, but I'm not
sure why I failed, because it's definitely broken. The key_column_usage
view has

FROM pg_namespace nr, pg_class r, pg_namespace nc,
pg_constraint c
WHERE nr.oid = r.relnamespace
AND r.oid = c.conrelid
AND nc.oid = c.connamespace
AND c.contype IN ('p', 'u', 'f')
AND r.relkind = 'r'
AND (NOT pg_is_other_temp_schema(nr.oid))
AND (pg_has_role(r.relowner, 'USAGE')
OR has_table_privilege(c.oid, 'SELECT')
OR has_table_privilege(c.oid, 'INSERT')
OR has_table_privilege(c.oid, 'UPDATE')
OR has_table_privilege(c.oid, 'REFERENCES')) ) AS ss

Obviously those last four lines should be r.oid not c.oid. The bug is
masked as long as the preceding pg_has_role() test succeeds, so in
particular a superuser would never see it :-(

We won't be able to force initdb to fix this in the back branches,
but fortunately the information schema views are not hardwired in.
Just drop the view and recreate it with the corrected definition...

regards, tom lane

This has has been fixed in CVS HEAD and 8.2.X will get the fix if the
drop and recreate the view, or initdb.

---------------------------------------------------------------------------

Tom Lane wrote:

Laurence Rowe <l@lrowe.co.uk> writes:

I have the following query:

SELECT key_column_usage.*,constraint_type
FROM information_schema.key_column_usage
LEFT JOIN information_schema.table_constraints USING
(table_schema,table_name,constraint_name)
WHERE table_schema='whatever' and table_name='whatever'
ORDER BY constraint_type, constraint_name, ordinal_position

This works when I am logged on as 'postgres', but if I try it after logging
on with a different username it fails with "ERROR: relation with OID 18635
does not exist".

Hmph ... I recall being unable to reproduce this before, but I'm not
sure why I failed, because it's definitely broken. The key_column_usage
view has

FROM pg_namespace nr, pg_class r, pg_namespace nc,
pg_constraint c
WHERE nr.oid = r.relnamespace
AND r.oid = c.conrelid
AND nc.oid = c.connamespace
AND c.contype IN ('p', 'u', 'f')
AND r.relkind = 'r'
AND (NOT pg_is_other_temp_schema(nr.oid))
AND (pg_has_role(r.relowner, 'USAGE')
OR has_table_privilege(c.oid, 'SELECT')
OR has_table_privilege(c.oid, 'INSERT')
OR has_table_privilege(c.oid, 'UPDATE')
OR has_table_privilege(c.oid, 'REFERENCES')) ) AS ss

Obviously those last four lines should be r.oid not c.oid. The bug is
masked as long as the preceding pg_has_role() test succeeds, so in
particular a superuser would never see it :-(

We won't be able to force initdb to fix this in the back branches,
but fortunately the information schema views are not hardwired in.
Just drop the view and recreate it with the corrected definition...

regards, tom lane

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