Maybe that a simple check of the asof_timestamp value like: asof_timestamp >= now() - time_travel_period AND asof_timestamp >= latest_table_ddl
would permit to raise a warning or an error message saying that query result can not be garanteed with this asof_timestamp value. latest_table_ddl being found with SELECT greatest( max(pg_xact_commit_timestamp( rel.xmin )), max(pg_xact_commit_timestamp( att.xmin ))) as latest_table_ddl FROM pg_catalog.pg_attribute att INNER JOIN pg_catalog.pg_class rel ON att.attrelid = rel.oid WHERE rel.relname = '<asof_tablename>' and rel.relowner= ... (tested with add/alter/drop column and drop/create/truncate table) Regards PAscal -- Sent from: http://www.postgresql-archive.org/PostgreSQL-hackers-f1928748.html
