97 lines
2.4 KiB
PL/PgSQL
97 lines
2.4 KiB
PL/PgSQL
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CREATE TABLE IF NOT EXISTS
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public.CDB_TableMetadata (
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tabname regclass not null primary key,
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updated_at timestamp with time zone not null default now()
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);
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-- Anyone can see this, but updates are only possible trough
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-- the security definer trigger
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GRANT SELECT ON public.CDB_TableMetadata TO public;
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--
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-- Trigger logging updated_at in the CDB_TableMetadata
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-- and notifying cdb_tabledata_update with table name as payload.
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--
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-- Attach to tables like this:
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--
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-- CREATE trigger track_updates
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-- AFTER INSERT OR UPDATE OR TRUNCATE OR DELETE ON <tablename>
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-- FOR EACH STATEMENT
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-- EXECUTE PROCEDURE cdb_tablemetadata_trigger();
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--
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-- NOTE: _never_ attach to CDB_TableMetadata ...
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--
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CREATE OR REPLACE FUNCTION CDB_TableMetadata_Trigger()
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RETURNS trigger AS
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$$
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BEGIN
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-- Guard against infinite loop
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IF TG_RELID = 'public.CDB_TableMetadata'::regclass::oid THEN
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RETURN NULL;
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END IF;
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-- Cleanup stale entries
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DELETE FROM public.CDB_TableMetadata
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WHERE NOT EXISTS (
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SELECT oid FROM pg_class WHERE oid = tabname
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);
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WITH nv as (
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SELECT TG_RELID as tabname, NOW() as t
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), updated as (
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UPDATE public.CDB_TableMetadata x SET updated_at = nv.t
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FROM nv WHERE x.tabname = nv.tabname
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RETURNING x.tabname
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)
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INSERT INTO public.CDB_TableMetadata SELECT nv.*
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FROM nv LEFT JOIN updated USING(tabname)
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WHERE updated.tabname IS NULL;
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RETURN NULL;
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END;
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$$
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LANGUAGE plpgsql VOLATILE SECURITY DEFINER;
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--
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-- Trigger invalidating varnish whenever CDB_TableMetadata
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-- record change.
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--
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CREATE OR REPLACE FUNCTION _CDB_TableMetadata_Updated()
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RETURNS trigger AS
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$$
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DECLARE
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tabname TEXT;
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BEGIN
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IF TG_OP = 'UPDATE' or TG_OP = 'INSERT' THEN
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tabname = NEW.tabname;
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ELSE
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tabname = OLD.tabname;
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END IF;
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-- Notify table data update
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-- This needs a little bit more of research regarding security issues
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-- see https://github.com/CartoDB/cartodb/pull/241
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-- PERFORM pg_notify('cdb_tabledata_update', tabname);
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--RAISE NOTICE 'Table % was updated', tabname;
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-- This will be needed until we'll have someone listening
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-- on the event we just broadcasted:
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--
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-- LISTEN cdb_tabledata_update;
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--
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PERFORM cdb_invalidate_varnish(tabname);
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RETURN NULL;
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END;
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$$
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LANGUAGE plpgsql VOLATILE SECURITY DEFINER;
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DROP TRIGGER IF EXISTS table_modified ON CDB_TableMetadata;
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CREATE TRIGGER table_modified AFTER INSERT OR UPDATE OR DELETE
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ON CDB_TableMetadata FOR EACH ROW EXECUTE PROCEDURE
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_CDB_TableMetadata_Updated();
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