cartodb-4.42/lib/sql/scripts-available/CDB_TableMetadata.sql
2024-04-06 05:25:13 +00:00

153 lines
4.6 KiB
PL/PgSQL

CREATE TABLE IF NOT EXISTS
@extschema@.CDB_TableMetadata (
tabname regclass not null primary key,
updated_at timestamp with time zone not null default now()
);
CREATE OR REPLACE VIEW @extschema@.CDB_TableMetadata_Text AS
SELECT FORMAT('%I.%I', n.nspname::text, c.relname::text) tabname, updated_at
FROM @extschema@.CDB_TableMetadata m JOIN pg_catalog.pg_class c ON m.tabname::oid = c.oid
LEFT JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid;
-- No one can see this
-- Updates are only possible trough the security definer trigger
-- GRANT SELECT ON @extschema@.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 @extschema@.CDB_TableMetadata_Trigger()
RETURNS trigger AS
$$
BEGIN
-- Guard against infinite loop
IF TG_RELID = '@extschema@.CDB_TableMetadata'::regclass::oid THEN
RETURN NULL;
END IF;
-- Cleanup stale entries
DELETE FROM @extschema@.CDB_TableMetadata
WHERE NOT EXISTS (
SELECT oid FROM pg_class WHERE oid = tabname
);
WITH nv as (
SELECT TG_RELID as tabname, now() as t
), updated as (
UPDATE @extschema@.CDB_TableMetadata x SET updated_at = nv.t
FROM nv WHERE x.tabname = nv.tabname
RETURNING x.tabname
)
INSERT INTO @extschema@.CDB_TableMetadata SELECT nv.*
FROM nv LEFT JOIN updated USING(tabname)
WHERE updated.tabname IS NULL;
RETURN NULL;
END;
$$ LANGUAGE plpgsql
VOLATILE
PARALLEL UNSAFE
SECURITY DEFINER
SET search_path = pg_temp;
--
-- Trigger invalidating varnish whenever CDB_TableMetadata
-- record change.
--
CREATE OR REPLACE FUNCTION @extschema@._CDB_TableMetadata_Updated()
RETURNS trigger AS
$$
DECLARE
tabname regclass;
rec RECORD;
found BOOL;
schema_name TEXT;
table_name TEXT;
BEGIN
IF TG_OP = 'UPDATE' or TG_OP = 'INSERT' THEN
tabname = NEW.tabname;
ELSE
tabname = OLD.tabname;
END IF;
-- Notify table data update
-- This needs a little bit more of research regarding security issues
-- see https://github.com/CartoDB/cartodb/pull/241
-- PERFORM pg_notify('cdb_tabledata_update', tabname);
--RAISE NOTICE 'Table % was updated', tabname;
-- This will be needed until we'll have someone listening
-- on the event we just broadcasted:
--
-- LISTEN cdb_tabledata_update;
--
-- Call the first varnish invalidation function owned
-- by a superuser found in @extschema@ or public schema
-- (in that order)
found := false;
FOR rec IN SELECT u.usesuper, u.usename, n.nspname, p.proname
FROM pg_proc p, pg_namespace n, pg_user u
WHERE p.proname = 'cdb_invalidate_varnish'
AND p.pronamespace = n.oid
AND n.nspname IN ('public', '@extschema@')
AND u.usesysid = p.proowner
AND u.usesuper
ORDER BY n.nspname
LOOP
SELECT n.nspname, c.relname FROM pg_class c, pg_namespace n WHERE c.oid=tabname AND c.relnamespace = n.oid INTO schema_name, table_name;
EXECUTE 'SELECT ' || quote_ident(rec.nspname) || '.'
|| quote_ident(rec.proname)
|| '(' || quote_literal(quote_ident(schema_name) || '.' || quote_ident(table_name)) || ')';
found := true;
EXIT;
END LOOP;
IF NOT found THEN RAISE WARNING 'Missing cdb_invalidate_varnish()'; END IF;
RETURN NULL;
END;
$$ LANGUAGE plpgsql
VOLATILE
PARALLEL UNSAFE
SECURITY DEFINER
SET search_path = pg_temp;
DROP TRIGGER IF EXISTS table_modified ON @extschema@.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 @extschema@.CDB_TableMetadata FOR EACH ROW EXECUTE PROCEDURE
@extschema@._CDB_TableMetadata_Updated();
-- similar to TOUCH(1) in unix filesystems but for table in cdb_tablemetadata
CREATE OR REPLACE FUNCTION @extschema@.CDB_TableMetadataTouch(tablename regclass)
RETURNS void AS
$$
BEGIN
WITH upsert AS (
UPDATE @extschema@.cdb_tablemetadata
SET updated_at = NOW()
WHERE tabname = tablename
RETURNING *
)
INSERT INTO @extschema@.cdb_tablemetadata (tabname, updated_at)
SELECT tablename, NOW()
WHERE NOT EXISTS (SELECT * FROM upsert);
END;
$$
LANGUAGE 'plpgsql' VOLATILE STRICT PARALLEL UNSAFE;