Fix subtract_integer_from_now on 32-bit platforms

This patch fixes subtract_integer_from_now on 32-bit platforms,
improves error handling and adds some basic tests.
subtract_integer_from_now would trigger an assert when called
on a hypertable without integer time dimension (found by sqlsmith).
Additionally subtract_integer_from_now would segfault when called
on a hypertable without partitioning dimensions.

src/hypertable.c

@@ -2391,6 +2391,11 @@ ts_hypertable_set_integer_now_func(PG_FUNCTION_ARGS)
 	ts_hypertable_permissions_check(table_relid, GetUserId());
 	hypertable = ts_hypertable_cache_get_cache_and_entry(table_relid, CACHE_FLAG_NONE, &hcache);
 
+	if (TS_HYPERTABLE_IS_INTERNAL_COMPRESSION_TABLE(hypertable))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("custom time function not supported on internal compression table")));
+
 	/* validate that the open dimension uses numeric type */
 	open_dim = hyperspace_get_open_dimension(hypertable->space, 0);
 

src/utils.c

@@ -904,18 +904,24 @@ Datum
 ts_subtract_integer_from_now(PG_FUNCTION_ARGS)
 {
 	Oid ht_relid = PG_GETARG_OID(0);
-	Datum lag = PG_GETARG_INT64(1);
+	int64 lag = PG_GETARG_INT64(1);
 	Cache *hcache;
-	Hypertable *hypertable =
-		ts_hypertable_cache_get_cache_and_entry(ht_relid, CACHE_FLAG_NONE, &hcache);
-
-	const Dimension *dim = hyperspace_get_open_dimension(hypertable->space, 0);
-	Oid partitioning_type = ts_dimension_get_partition_type(dim);
-	Oid now_func = ts_get_integer_now_func(dim);
-	if (now_func == InvalidOid)
-		elog(ERROR, "could not find valid integer_now function for hypertable");
-	Assert(IS_INTEGER_TYPE(partitioning_type));
-	int64 res = ts_sub_integer_from_now(lag, partitioning_type, now_func);
+	Hypertable *ht = ts_hypertable_cache_get_cache_and_entry(ht_relid, CACHE_FLAG_NONE, &hcache);
+	const Dimension *dim = hyperspace_get_open_dimension(ht->space, 0);
 	ts_cache_release(hcache);
+
+	if (!dim)
+		elog(ERROR, "hypertable has no open partitioning dimension");
+
+	Oid partitioning_type = ts_dimension_get_partition_type(dim);
+
+	if (!IS_INTEGER_TYPE(partitioning_type))
+		elog(ERROR, "hypertable has no integer partitioning dimension");
+
+	Oid now_func = ts_get_integer_now_func(dim);
+	if (!OidIsValid(now_func))
+		elog(ERROR, "could not find valid integer_now function for hypertable");
+
+	int64 res = ts_sub_integer_from_now(lag, partitioning_type, now_func);
 	return Int64GetDatum(res);
 }

tsl/test/shared/expected/subtract_integer_from_now.out

@@ -0,0 +1,118 @@
+-- This file and its contents are licensed under the Timescale License.
+-- Please see the included NOTICE for copyright information and
+-- LICENSE-TIMESCALE for a copy of the license.
+-- test on normal table
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('pg_class', 1);
+ERROR:  table "pg_class" is not a hypertable
+\set ON_ERROR_STOP 1
+-- test on hypertable with non-int time dimension
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('metrics', 1);
+ERROR:  hypertable has no integer partitioning dimension
+\set ON_ERROR_STOP 1
+SELECT
+  format('%I.%I', ht.schema_name, ht.table_name) AS "TABLENAME"
+FROM
+  _timescaledb_catalog.hypertable ht
+  INNER JOIN _timescaledb_catalog.hypertable uncompress ON (ht.id = uncompress.compressed_hypertable_id
+      AND uncompress.table_name = 'metrics_compressed') \gset
+-- test on hypertable without dimensions
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now(:'TABLENAME', 1);
+ERROR:  hypertable has no open partitioning dimension
+\set ON_ERROR_STOP 1
+-- test on hypertable without now function
+CREATE TABLE subtract_int_no_func(time int NOT NULL);
+SELECT table_name FROM create_hypertable('subtract_int_no_func','time',chunk_time_interval:=10);
+      table_name      
+----------------------
+ subtract_int_no_func
+(1 row)
+
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int_no_func', 1);
+ERROR:  integer_now function not set
+\set ON_ERROR_STOP 1
+CREATE OR REPLACE FUNCTION sub_int2_now() RETURNS int2 AS $$ SELECT 2::int2; $$ LANGUAGE SQL IMMUTABLE;
+CREATE OR REPLACE FUNCTION sub_int4_now() RETURNS int4 AS $$ SELECT 4::int4; $$ LANGUAGE SQL IMMUTABLE;
+CREATE OR REPLACE FUNCTION sub_int8_now() RETURNS int8 AS $$ SELECT 8::int8; $$ LANGUAGE SQL IMMUTABLE;
+CREATE TABLE subtract_int2(time int2 NOT NULL);
+CREATE TABLE subtract_int4(time int4 NOT NULL);
+CREATE TABLE subtract_int8(time int8 NOT NULL);
+SELECT table_name FROM create_hypertable('subtract_int2', 'time', chunk_time_interval:=10);
+  table_name   
+---------------
+ subtract_int2
+(1 row)
+
+SELECT table_name FROM create_hypertable('subtract_int4', 'time', chunk_time_interval:=10);
+  table_name   
+---------------
+ subtract_int4
+(1 row)
+
+SELECT table_name FROM create_hypertable('subtract_int8', 'time', chunk_time_interval:=10);
+  table_name   
+---------------
+ subtract_int8
+(1 row)
+
+SELECT set_integer_now_func('subtract_int2', 'sub_int2_now');
+ set_integer_now_func 
+----------------------
+ 
+(1 row)
+
+SELECT set_integer_now_func('subtract_int4', 'sub_int4_now');
+ set_integer_now_func 
+----------------------
+ 
+(1 row)
+
+SELECT set_integer_now_func('subtract_int8', 'sub_int8_now');
+ set_integer_now_func 
+----------------------
+ 
+(1 row)
+
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int2', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+ sub 
+-----
+  12
+   2
+   0
+  -2
+  -6
+(5 rows)
+
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int4', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+ sub 
+-----
+  14
+   4
+   2
+   0
+  -4
+(5 rows)
+
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int8', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+ sub 
+-----
+  18
+   8
+   6
+   4
+   0
+(5 rows)
+
+-- test set_integer_now_func on internal table
+\set ON_ERROR_STOP 0
+SELECT set_integer_now_func(:'TABLENAME', 'sub_int2_now');
+ERROR:  custom time function not supported on internal compression table
+\set ON_ERROR_STOP 1
+-- cleanup
+DROP TABLE subtract_int_no_func;
+DROP TABLE subtract_int2;
+DROP TABLE subtract_int4;
+DROP TABLE subtract_int8;

tsl/test/shared/sql/CMakeLists.txt

@@ -9,7 +9,8 @@ set(TEST_FILES_SHARED
     dist_fetcher_type.sql
     dist_gapfill.sql
     dist_insert.sql
-    dist_queries.sql)
+    dist_queries.sql
+    subtract_integer_from_now.sql)
 
 if((${PG_VERSION_MAJOR} GREATER_EQUAL "14"))
   list(APPEND TEST_FILES_SHARED memoize.sql)

tsl/test/shared/sql/subtract_integer_from_now.sql

@@ -0,0 +1,63 @@
+-- This file and its contents are licensed under the Timescale License.
+-- Please see the included NOTICE for copyright information and
+-- LICENSE-TIMESCALE for a copy of the license.
+
+-- test on normal table
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('pg_class', 1);
+\set ON_ERROR_STOP 1
+
+-- test on hypertable with non-int time dimension
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('metrics', 1);
+\set ON_ERROR_STOP 1
+
+SELECT
+  format('%I.%I', ht.schema_name, ht.table_name) AS "TABLENAME"
+FROM
+  _timescaledb_catalog.hypertable ht
+  INNER JOIN _timescaledb_catalog.hypertable uncompress ON (ht.id = uncompress.compressed_hypertable_id
+      AND uncompress.table_name = 'metrics_compressed') \gset
+
+-- test on hypertable without dimensions
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now(:'TABLENAME', 1);
+\set ON_ERROR_STOP 1
+
+-- test on hypertable without now function
+CREATE TABLE subtract_int_no_func(time int NOT NULL);
+SELECT table_name FROM create_hypertable('subtract_int_no_func','time',chunk_time_interval:=10);
+\set ON_ERROR_STOP 0
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int_no_func', 1);
+\set ON_ERROR_STOP 1
+
+CREATE OR REPLACE FUNCTION sub_int2_now() RETURNS int2 AS $$ SELECT 2::int2; $$ LANGUAGE SQL IMMUTABLE;
+CREATE OR REPLACE FUNCTION sub_int4_now() RETURNS int4 AS $$ SELECT 4::int4; $$ LANGUAGE SQL IMMUTABLE;
+CREATE OR REPLACE FUNCTION sub_int8_now() RETURNS int8 AS $$ SELECT 8::int8; $$ LANGUAGE SQL IMMUTABLE;
+
+CREATE TABLE subtract_int2(time int2 NOT NULL);
+CREATE TABLE subtract_int4(time int4 NOT NULL);
+CREATE TABLE subtract_int8(time int8 NOT NULL);
+
+SELECT table_name FROM create_hypertable('subtract_int2', 'time', chunk_time_interval:=10);
+SELECT table_name FROM create_hypertable('subtract_int4', 'time', chunk_time_interval:=10);
+SELECT table_name FROM create_hypertable('subtract_int8', 'time', chunk_time_interval:=10);
+
+SELECT set_integer_now_func('subtract_int2', 'sub_int2_now');
+SELECT set_integer_now_func('subtract_int4', 'sub_int4_now');
+SELECT set_integer_now_func('subtract_int8', 'sub_int8_now');
+
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int2', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int4', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+SELECT _timescaledb_internal.subtract_integer_from_now('subtract_int8', lag) AS sub FROM (VALUES (-10),(0),(2),(4),(8)) v(lag);
+
+-- test set_integer_now_func on internal table
+\set ON_ERROR_STOP 0
+SELECT set_integer_now_func(:'TABLENAME', 'sub_int2_now');
+\set ON_ERROR_STOP 1
+
+-- cleanup
+DROP TABLE subtract_int_no_func;
+DROP TABLE subtract_int2;
+DROP TABLE subtract_int4;
+DROP TABLE subtract_int8;