CREATE TABLE IF NOT EXISTS public.CDB_TableMetadata ( tabname regclass not null primary key, updated_at timestamp with time zone not null default now() ); -- No one can see this -- Updates are only possible trough the security definer trigger -- GRANT SELECT ON public.CDB_TableMetadata TO public; -- -- Trigger logging updated_at in the CDB_TableMetadata -- and notifying cdb_tabledata_update with table name as payload. -- -- Attach to tables like this: -- -- CREATE trigger track_updates -- AFTER INSERT OR UPDATE OR TRUNCATE OR DELETE ON -- FOR EACH STATEMENT -- EXECUTE PROCEDURE cdb_tablemetadata_trigger(); -- -- NOTE: _never_ attach to CDB_TableMetadata ... -- CREATE OR REPLACE FUNCTION CDB_TableMetadata_Trigger() RETURNS trigger AS $$ BEGIN -- Guard against infinite loop IF TG_RELID = 'public.CDB_TableMetadata'::regclass::oid THEN RETURN NULL; END IF; -- Cleanup stale entries DELETE FROM public.CDB_TableMetadata WHERE NOT EXISTS ( SELECT oid FROM pg_class WHERE oid = tabname ); WITH nv as ( SELECT TG_RELID as tabname, NOW() as t ), updated as ( UPDATE public.CDB_TableMetadata x SET updated_at = nv.t FROM nv WHERE x.tabname = nv.tabname RETURNING x.tabname ) INSERT INTO public.CDB_TableMetadata SELECT nv.* FROM nv LEFT JOIN updated USING(tabname) WHERE updated.tabname IS NULL; RETURN NULL; END; $$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER; -- -- Trigger invalidating varnish whenever CDB_TableMetadata -- record change. -- CREATE OR REPLACE FUNCTION _CDB_TableMetadata_Updated() RETURNS trigger AS $$ DECLARE tabname TEXT; rec RECORD; found BOOL; BEGIN IF TG_OP = 'UPDATE' or TG_OP = 'INSERT' THEN tabname = NEW.tabname; ELSE tabname = OLD.tabname; END IF; -- Notify table data update -- This needs a little bit more of research regarding security issues -- see https://github.com/CartoDB/cartodb/pull/241 -- PERFORM pg_notify('cdb_tabledata_update', tabname); --RAISE NOTICE 'Table % was updated', tabname; -- This will be needed until we'll have someone listening -- on the event we just broadcasted: -- -- LISTEN cdb_tabledata_update; -- -- Call the first varnish invalidation function owned -- by a superuser found in cartodb or public schema -- (in that order) found := false; FOR rec IN SELECT u.usesuper, u.usename, n.nspname, p.proname FROM pg_proc p, pg_namespace n, pg_user u WHERE p.proname = 'cdb_invalidate_varnish' AND p.pronamespace = n.oid AND n.nspname IN ('public', 'cartodb') AND u.usesysid = p.proowner AND u.usesuper ORDER BY n.nspname LOOP EXECUTE 'SELECT ' || quote_ident(rec.nspname) || '.' || quote_ident(rec.proname) || '(' || quote_literal(tabname) || ')'; found := true; EXIT; END LOOP; IF NOT found THEN RAISE WARNING 'Missing cdb_invalidate_varnish()'; END IF; RETURN NULL; END; $$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER; DROP TRIGGER IF EXISTS table_modified ON CDB_TableMetadata; -- NOTE: on DELETE we would be unable to convert the table -- oid (regclass) to its name CREATE TRIGGER table_modified AFTER INSERT OR UPDATE ON CDB_TableMetadata FOR EACH ROW EXECUTE PROCEDURE _CDB_TableMetadata_Updated();