Fix cagg trigger on compat schema layer

The trigger `continuous_agg_invalidation_trigger` receive the hypertable
id as parameter as the following example:

Triggers:
    ts_cagg_invalidation_trigger AFTER INSERT OR DELETE OR UPDATE ON
       _timescaledb_internal._hyper_3_59_chunk
    FOR EACH ROW EXECUTE FUNCTION
       _timescaledb_functions.continuous_agg_invalidation_trigger('3')

The problem is in the compatibility layer using PL/pgSQL code there's no
way to passdown the parameter from the wrapper trigger function created
to the underlying trigger function in another schema.

To solve this we simple create a new function in the deprecated
`_timescaledb_internal` schema pointing to the function trigger and
inside the C code we emit the WARNING message if the function is called
from the deprecated schema.

sql/compat.sql

@@ -188,16 +188,8 @@ BEGIN
 END$$
 SET search_path TO pg_catalog,pg_temp;
 
-
-CREATE OR REPLACE FUNCTION _timescaledb_internal.continuous_agg_invalidation_trigger() RETURNS trigger LANGUAGE PLPGSQL AS $$
-BEGIN
-  IF current_setting('timescaledb.enable_deprecation_warnings', true)::bool THEN
-    RAISE WARNING 'function _timescaledb_internal.continuous_agg_invalidation_trigger() is deprecated and has been moved to _timescaledb_functions schema. this compatibility function will be removed in a future version.';
-  END IF;
-  RETURN _timescaledb_functions.continuous_agg_invalidation_trigger();
-END$$
-SET search_path TO pg_catalog,pg_temp;
-
+CREATE OR REPLACE FUNCTION _timescaledb_internal.continuous_agg_invalidation_trigger() RETURNS TRIGGER
+AS '@MODULE_PATHNAME@', 'ts_continuous_agg_invalidation_trigger' LANGUAGE C;
 
 -- we have to prefix slices, schema_name and table_name parameter with _ here to not clash with output names otherwise plpgsql will complain
 CREATE OR REPLACE FUNCTION _timescaledb_internal.create_chunk(hypertable regclass,_slices jsonb,_schema_name name=NULL,_table_name name=NULL,chunk_table regclass=NULL) RETURNS TABLE(chunk_id INTEGER, hypertable_id INTEGER, schema_name NAME, table_name NAME, relkind "char", slices JSONB, created BOOLEAN) LANGUAGE PLPGSQL AS $$

src/guc.h

@@ -15,7 +15,7 @@ extern bool ts_telemetry_on(void);
 extern bool ts_function_telemetry_on(void);
 #endif
 
-extern bool ts_guc_enable_deprecation_warnings;
+extern TSDLLEXPORT bool ts_guc_enable_deprecation_warnings;
 extern bool ts_guc_enable_optimizations;
 extern bool ts_guc_enable_constraint_aware_append;
 extern bool ts_guc_enable_ordered_append;

tsl/src/continuous_aggs/insert.c

@@ -26,6 +26,7 @@
 
 #include "chunk.h"
 #include "dimension.h"
+#include "guc.h"
 #include "hypertable.h"
 #include "hypertable_cache.h"
 #include "invalidation.h"
@@ -222,6 +223,14 @@ continuous_agg_trigfn(PG_FUNCTION_ARGS)
 	if (trigdata == NULL || trigdata->tg_trigger == NULL || trigdata->tg_trigger->tgnargs < 0)
 		elog(ERROR, "must supply hypertable id");
 
+	if (ts_guc_enable_deprecation_warnings && OidIsValid(trigdata->tg_trigger->tgfoid) &&
+		strcmp(get_namespace_name(get_func_namespace(trigdata->tg_trigger->tgfoid)),
+				INTERNAL_SCHEMA_NAME) == 0)
+		elog(WARNING,
+			 "function _timescaledb_internal.continuous_agg_invalidation_trigger() is deprecated "
+			 "and has been moved to _timescaledb_functions schema. this compatibility function "
+			 "will be removed in a future version.");
+
 	hypertable_id_str = trigdata->tg_trigger->tgargs[0];
 	hypertable_id = atol(hypertable_id_str);
 

tsl/test/shared/expected/compat.out

@@ -85,6 +85,8 @@ ERROR:  hypertable cannot be NULL
 SELECT _timescaledb_internal.create_compressed_chunk(0,0,0,0,0,0,0,0,0,0);
 WARNING:  function _timescaledb_internal.create_compressed_chunk(regclass,regclass,bigint,bigint,bigint,bigint,bigint,bigint,bigint,bigint) is deprecated and has been moved to _timescaledb_functions schema. this compatibility function will be removed in a future version.
 ERROR:  invalid Oid
+SELECT _timescaledb_internal.continuous_agg_invalidation_trigger();
+ERROR:  must supply hypertable id
 SELECT _timescaledb_internal.data_node_chunk_info(NULL,NULL,NULL);
 WARNING:  function _timescaledb_internal.data_node_chunk_info(name,name,name) is deprecated and has been moved to _timescaledb_functions schema. this compatibility function will be removed in a future version.
  data_node_chunk_info 
@@ -421,3 +423,29 @@ WARNING:  procedure _timescaledb_internal.policy_retention(integer,jsonb) is dep
 CALL _timescaledb_internal.wait_subscription_sync(NULL,NULL,0,0);
 WARNING:  procedure _timescaledb_internal.wait_subscription_sync(name,name,integer,numeric) is deprecated and has been moved to _timescaledb_functions schema. this compatibility function will be removed in a future version.
 ERROR:  subscription sync wait timedout
+\set ON_ERROR_STOP 1
+-- tests for the cagg invalidation trigger on the deprecated schema
+CREATE TABLE sensor_data (
+    time timestamptz NOT NULL,
+    sensor_id integer NOT NULL,
+    cpu double precision NULL,
+    temperature double precision NULL
+);
+SELECT hypertable_id FROM create_hypertable('sensor_data','time') \gset
+CREATE MATERIALIZED VIEW sensor_data_hourly WITH (timescaledb.continuous, timescaledb.materialized_only=false) AS
+SELECT sensor_id,
+       time_bucket(INTERVAL '1 hour', time) AS timestamp,
+       min(time)                            AS first_data_received,
+       max(time)                            AS last_data_received
+FROM sensor_data
+GROUP BY sensor_id, time_bucket(INTERVAL '1 hour', time)
+WITH DATA;
+NOTICE:  continuous aggregate "sensor_data_hourly" is already up-to-date
+DROP TRIGGER ts_cagg_invalidation_trigger ON sensor_data;
+CREATE TRIGGER ts_cagg_invalidation_trigger
+    AFTER INSERT OR DELETE OR UPDATE ON sensor_data
+    FOR EACH ROW EXECUTE FUNCTION _timescaledb_internal.continuous_agg_invalidation_trigger(:'hypertable_id');
+-- should WARN about the deprecated schema usage
+SET timescaledb.enable_deprecation_warnings = 'on'; -- make sure the GUC is enabled
+INSERT INTO sensor_data values('1980-01-01 00:00:00-00', 1, 1, 1);
+WARNING:  function _timescaledb_internal.continuous_agg_invalidation_trigger() is deprecated and has been moved to _timescaledb_functions schema. this compatibility function will be removed in a future version.

tsl/test/shared/sql/compat.sql

@@ -26,6 +26,7 @@ SELECT _timescaledb_internal.create_chunk(0,NULL,NULL,NULL,0);
 SELECT _timescaledb_internal.create_chunk_replica_table(0,NULL);
 SELECT _timescaledb_internal.create_chunk_table(0,NULL,NULL,NULL);
 SELECT _timescaledb_internal.create_compressed_chunk(0,0,0,0,0,0,0,0,0,0);
+SELECT _timescaledb_internal.continuous_agg_invalidation_trigger();
 SELECT _timescaledb_internal.data_node_chunk_info(NULL,NULL,NULL);
 SELECT _timescaledb_internal.data_node_compressed_chunk_stats(NULL,NULL,NULL);
 SELECT _timescaledb_internal.data_node_hypertable_info(NULL,NULL,NULL);
@@ -107,3 +108,33 @@ CALL _timescaledb_internal.policy_reorder(0,NULL);
 CALL _timescaledb_internal.policy_retention(0,NULL);
 CALL _timescaledb_internal.wait_subscription_sync(NULL,NULL,0,0);
 
+\set ON_ERROR_STOP 1
+
+-- tests for the cagg invalidation trigger on the deprecated schema
+CREATE TABLE sensor_data (
+    time timestamptz NOT NULL,
+    sensor_id integer NOT NULL,
+    cpu double precision NULL,
+    temperature double precision NULL
+);
+
+SELECT hypertable_id FROM create_hypertable('sensor_data','time') \gset
+
+CREATE MATERIALIZED VIEW sensor_data_hourly WITH (timescaledb.continuous, timescaledb.materialized_only=false) AS
+SELECT sensor_id,
+       time_bucket(INTERVAL '1 hour', time) AS timestamp,
+       min(time)                            AS first_data_received,
+       max(time)                            AS last_data_received
+FROM sensor_data
+GROUP BY sensor_id, time_bucket(INTERVAL '1 hour', time)
+WITH DATA;
+
+DROP TRIGGER ts_cagg_invalidation_trigger ON sensor_data;
+
+CREATE TRIGGER ts_cagg_invalidation_trigger
+    AFTER INSERT OR DELETE OR UPDATE ON sensor_data
+    FOR EACH ROW EXECUTE FUNCTION _timescaledb_internal.continuous_agg_invalidation_trigger(:'hypertable_id');
+
+-- should WARN about the deprecated schema usage
+SET timescaledb.enable_deprecation_warnings = 'on'; -- make sure the GUC is enabled
+INSERT INTO sensor_data values('1980-01-01 00:00:00-00', 1, 1, 1);