Copy cartodb lib/sql scripts from CDB_CartodbfyTable branch

scripts-available/CDB_TableMetadata.sql

@@ -0,0 +1,96 @@
+
+CREATE TABLE IF NOT EXISTS
+  public.CDB_TableMetadata (
+    tabname regclass not null primary key,
+    updated_at timestamp with time zone not null default now()
+  );
+
+-- Anyone can see this, but 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 <tablename>
+--    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
+$$
+DECLARE
+  tabname TEXT;
+BEGIN
+
+  IF TG_OP = 'UPDATE' or TG_OP = 'INSERT' THEN
+    tabname = NEW.tabname;
+  ELSE
+    tabname = OLD.tabname;
+  END IF;
+
+  -- Notify table data update
+  -- This needs a little bit more of research regarding security issues
+  -- see https://github.com/CartoDB/cartodb/pull/241
+  -- PERFORM pg_notify('cdb_tabledata_update', tabname);
+
+  --RAISE NOTICE 'Table % was updated', tabname;
+
+  -- This will be needed until we'll have someone listening
+  -- on the event we just broadcasted:
+  --
+  --  LISTEN cdb_tabledata_update;
+  --
+  PERFORM cdb_invalidate_varnish(tabname);
+
+  RETURN NULL;
+END;
+$$
+LANGUAGE plpgsql VOLATILE SECURITY DEFINER;
+
+DROP TRIGGER IF EXISTS table_modified ON CDB_TableMetadata;
+CREATE TRIGGER table_modified AFTER INSERT OR UPDATE OR DELETE
+ON CDB_TableMetadata FOR EACH ROW EXECUTE PROCEDURE
+ _CDB_TableMetadata_Updated();
+