Janning Vygen <vygen@xxxxxxxxxxxx> writes: > PERFORM n.nspname ,c.relname > FROM > pg_catalog.pg_class c > LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace > WHERE > n.nspname like 'pg_temp_%' > AND pg_catalog.pg_table_is_visible(c.oid) > AND Upper(relname) = 'TEMP_GC' > ; > but as i looked at the system catalogs pg_temp it is like that every session > can see the temporary tables of any other session. so the whole story about > the query above is wrong. It checks if ANY session has a temporrary table > gc_temp and not my own session. No, not at all: the pg_table_is_visible check will fail on temp tables of other sessions. I think the real problem here is a race condition: pg_table_is_visible will give the "cache lookup failed" error if the OID is for a table that no longer exists, which means you could have a problem when the select picks up a pg_class row for another session's temp table just before the other session drops the temp table. (The window for this is wider than it might seem, because pg_table_is_visible operates under SnapshotNow rules instead of MVCC.) We've gone back and forth about whether it'd be better for pg_table_is_visible to silently return FALSE if the OID is not a valid table OID, but that doesn't seem real attractive from an error-detection perspective. In any case I don't think this has anything to do with your original report about a duplicate key error. If you can reproduce that one again, let us know. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
