I noticed that it seemed a bit slow to query
information_schema.view_column_usage. As I look at the code in
information_schema.sql, I'm not sure why pg_user is referenced twice
(once without an alias). It looks like we can take out the first
pg_user and remove the DISTINCT keyword and this improves the efficiency
significantly. It seems to return the same result but in half the
time. Anyone see a problem with this? (The same problem may also be in
view_table_usage but I haven't done any testing there yet.)
Code from information_schema.sql:
CREATE VIEW view_column_usage AS SELECT DISTINCT CAST(current_database() AS sql_identifier) AS view_catalog,
CAST(nv.nspname AS sql_identifier) AS view_schema, CAST(v.relname AS sql_identifier) AS view_name,
CAST(current_database() AS sql_identifier) AS table_catalog, CAST(nt.nspname AS sql_identifier) AS
table_schema, CAST(t.relname AS sql_identifier) AS table_name, CAST(a.attname AS sql_identifier) AS
column_name
FROM pg_user, pg_namespace nv, pg_class v, pg_depend dv, pg_depend dt, pg_class t, pg_namespace nt,
pg_attributea, pg_user u
