Add SQL function cagg_validate_query

With this function is possible to execute the Continuous Aggregate query
validation over an arbitrary query string, without the need to actually
create the Continuous Aggregate.

It can be used, for example, to check for most frequent queries maybe
using `pg_stat_statements`, validate them and check if there are queries
that potenttialy can turned into a Continuous Aggregate.

.unreleased/feature_6307

@@ -0,0 +1 @@
+Implements: #6307 Add SQL function cagg_validate_query

sql/cagg_utils.sql

@@ -120,3 +120,13 @@ CREATE OR REPLACE FUNCTION _timescaledb_functions.invalidation_process_cagg_log(
     OUT ret_window_start BIGINT,
     OUT ret_window_end BIGINT
 ) RETURNS RECORD AS '@MODULE_PATHNAME@', 'ts_invalidation_process_cagg_log' LANGUAGE C STRICT VOLATILE;
+
+CREATE OR REPLACE FUNCTION _timescaledb_functions.cagg_validate_query(
+    query TEXT,
+    OUT is_valid BOOLEAN,
+    OUT error_level TEXT,
+    OUT error_code TEXT,
+    OUT error_message TEXT,
+    OUT error_detail TEXT,
+    OUT error_hint TEXT
+) RETURNS RECORD AS '@MODULE_PATHNAME@', 'ts_continuous_agg_validate_query' LANGUAGE C STRICT VOLATILE;

sql/updates/reverse-dev.sql

@@ -194,3 +194,6 @@ CREATE FUNCTION @[email protected]_chunks(
 
 DROP PROCEDURE IF EXISTS _timescaledb_functions.repair_relation_acls();
 DROP FUNCTION IF EXISTS _timescaledb_functions.makeaclitem(regrole, regrole, text, bool);
+
+DROP FUNCTION IF EXISTS _timescaledb_functions.cagg_validate_query(TEXT, BOOLEAN, TEXT, TEXT, TEXT, TEXT, TEXT);
+

src/compat/compat.h

@@ -995,4 +995,69 @@ object_ownercheck(Oid classid, Oid objectid, Oid roleid)
 #define F_SUM_INT4 2108
 #endif
 
+/*
+ * PG15 refactored elog.c functions and exposed error_severity
+ * but previous versions don't have it exposed, so imported it
+ * from Postgres source code.
+ *
+ * https://github.com/postgres/postgres/commit/ac7c80758a7
+ */
+#if PG15_LT
+/*
+ * error_severity --- get string representing elevel
+ *
+ * The string is not localized here, but we mark the strings for translation
+ * so that callers can invoke _() on the result.
+ *
+ * Imported from src/backend/utils/error/elog.c
+ */
+static inline const char *
+error_severity(int elevel)
+{
+	const char *prefix;
+
+	switch (elevel)
+	{
+		case DEBUG1:
+		case DEBUG2:
+		case DEBUG3:
+		case DEBUG4:
+		case DEBUG5:
+			prefix = gettext_noop("DEBUG");
+			break;
+		case LOG:
+		case LOG_SERVER_ONLY:
+			prefix = gettext_noop("LOG");
+			break;
+		case INFO:
+			prefix = gettext_noop("INFO");
+			break;
+		case NOTICE:
+			prefix = gettext_noop("NOTICE");
+			break;
+		case WARNING:
+#if PG14_GE
+		/* https://github.com/postgres/postgres/commit/1f9158ba481 */
+		case WARNING_CLIENT_ONLY:
+#endif
+			prefix = gettext_noop("WARNING");
+			break;
+		case ERROR:
+			prefix = gettext_noop("ERROR");
+			break;
+		case FATAL:
+			prefix = gettext_noop("FATAL");
+			break;
+		case PANIC:
+			prefix = gettext_noop("PANIC");
+			break;
+		default:
+			prefix = "???";
+			break;
+	}
+
+	return prefix;
+}
+#endif
+
 #endif /* TIMESCALEDB_COMPAT_H */

src/cross_module_fn.c

@@ -88,6 +88,7 @@ CROSSMODULE_WRAPPER(decompress_chunk);
 /* continuous aggregate */
 CROSSMODULE_WRAPPER(continuous_agg_invalidation_trigger);
 CROSSMODULE_WRAPPER(continuous_agg_refresh);
+CROSSMODULE_WRAPPER(continuous_agg_validate_query);
 CROSSMODULE_WRAPPER(invalidation_cagg_log_add_entry);
 CROSSMODULE_WRAPPER(invalidation_hyper_log_add_entry);
 CROSSMODULE_WRAPPER(drop_dist_ht_invalidation_trigger);
@@ -494,6 +495,7 @@ TSDLLEXPORT CrossModuleFunctions ts_cm_functions_default = {
 	.continuous_agg_invalidate_raw_ht = continuous_agg_invalidate_raw_ht_all_default,
 	.continuous_agg_invalidate_mat_ht = continuous_agg_invalidate_mat_ht_all_default,
 	.continuous_agg_update_options = continuous_agg_update_options_default,
+	.continuous_agg_validate_query = error_no_default_fn_pg_community,
 	.invalidation_cagg_log_add_entry = error_no_default_fn_pg_community,
 	.invalidation_hyper_log_add_entry = error_no_default_fn_pg_community,
 	.remote_invalidation_log_delete = NULL,

src/cross_module_fn.h

@@ -120,6 +120,7 @@ typedef struct CrossModuleFunctions
 											 int64 start, int64 end);
 	void (*continuous_agg_update_options)(ContinuousAgg *cagg,
 										  WithClauseResult *with_clause_options);
+	PGFunction continuous_agg_validate_query;
 	PGFunction invalidation_cagg_log_add_entry;
 	PGFunction invalidation_hyper_log_add_entry;
 	void (*remote_invalidation_log_delete)(int32 raw_hypertable_id,

tsl/src/continuous_aggs/CMakeLists.txt

@@ -1,12 +1,13 @@
 set(SOURCES
     ${CMAKE_CURRENT_SOURCE_DIR}/common.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/finalize.c
     ${CMAKE_CURRENT_SOURCE_DIR}/create.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/finalize.c
     ${CMAKE_CURRENT_SOURCE_DIR}/insert.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/invalidation_threshold.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/invalidation.c
     ${CMAKE_CURRENT_SOURCE_DIR}/materialize.c
     ${CMAKE_CURRENT_SOURCE_DIR}/options.c
     ${CMAKE_CURRENT_SOURCE_DIR}/refresh.c
     ${CMAKE_CURRENT_SOURCE_DIR}/repair.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/invalidation.c
-    ${CMAKE_CURRENT_SOURCE_DIR}/invalidation_threshold.c)
+    ${CMAKE_CURRENT_SOURCE_DIR}/utils.c)
 target_sources(${TSL_LIBRARY_NAME} PRIVATE ${SOURCES})

tsl/src/continuous_aggs/common.c

@@ -12,8 +12,8 @@ static void caggtimebucketinfo_init(CAggTimebucketInfo *src, int32 hypertable_id
 									Oid hypertable_partition_coltype,
 									int64 hypertable_partition_col_interval,
 									int32 parent_mat_hypertable_id);
-static void caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause,
-									List *targetList);
+static void caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause, List *targetList,
+									bool is_cagg_create);
 static bool cagg_agg_validate(Node *node, void *context);
 static bool cagg_query_supported(const Query *query, StringInfo hint, StringInfo detail,
 								 const bool finalized);
@@ -149,7 +149,8 @@ destroy_union_query(Query *q)
  * the `bucket_width` and other fields of `tbinfo`.
  */
 static void
-caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause, List *targetList)
+caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause, List *targetList,
+						bool is_cagg_create)
 {
 	ListCell *l;
 	bool found = false;
@@ -320,22 +321,27 @@ caggtimebucket_validate(CAggTimebucketInfo *tbinfo, List *groupClause, List *tar
 				tbinfo->bucket_width_type = width->consttype;
 
 				if (width->constisnull)
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("invalid bucket width for time bucket function")));
-
-				if (width->consttype == INTERVALOID)
 				{
-					tbinfo->interval = DatumGetIntervalP(width->constvalue);
-					if (tbinfo->interval->month != 0)
-						tbinfo->bucket_width = BUCKET_WIDTH_VARIABLE;
+					if (is_cagg_create)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+								 errmsg("invalid bucket width for time bucket function")));
 				}
-
-				if (tbinfo->bucket_width != BUCKET_WIDTH_VARIABLE)
+				else
 				{
-					/* The bucket size is fixed. */
-					tbinfo->bucket_width =
-						ts_interval_value_to_internal(width->constvalue, width->consttype);
+					if (width->consttype == INTERVALOID)
+					{
+						tbinfo->interval = DatumGetIntervalP(width->constvalue);
+						if (tbinfo->interval && tbinfo->interval->month != 0)
+							tbinfo->bucket_width = BUCKET_WIDTH_VARIABLE;
+					}
+
+					if (tbinfo->bucket_width != BUCKET_WIDTH_VARIABLE)
+					{
+						/* The bucket size is fixed. */
+						tbinfo->bucket_width =
+							ts_interval_value_to_internal(width->constvalue, width->consttype);
+					}
 				}
 			}
 			else
@@ -618,10 +624,9 @@ get_bucket_width(CAggTimebucketInfo bucket_info)
 
 CAggTimebucketInfo
 cagg_validate_query(const Query *query, const bool finalized, const char *cagg_schema,
-					const char *cagg_name)
+					const char *cagg_name, const bool is_cagg_create)
 {
 	CAggTimebucketInfo bucket_info = { 0 }, bucket_info_parent;
-	Cache *hcache;
 	Hypertable *ht = NULL, *ht_parent = NULL;
 	RangeTblRef *rtref = NULL, *rtref_other = NULL;
 	RangeTblEntry *rte = NULL, *rte_other = NULL;
@@ -799,15 +804,27 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 	{
 		const Dimension *part_dimension = NULL;
 		int32 parent_mat_hypertable_id = INVALID_HYPERTABLE_ID;
+		Cache *hcache = ts_hypertable_cache_pin();
 
 		if (rte->relkind == RELKIND_RELATION)
-			ht = ts_hypertable_cache_get_cache_and_entry(rte->relid, CACHE_FLAG_NONE, &hcache);
+		{
+			ht = ts_hypertable_cache_get_entry(hcache, rte->relid, CACHE_FLAG_MISSING_OK);
+
+			if (!ht)
+			{
+				ts_cache_release(hcache);
+				ereport(ERROR,
+						(errcode(ERRCODE_TS_HYPERTABLE_NOT_EXIST),
+						 errmsg("table \"%s\" is not a hypertable", get_rel_name(rte->relid))));
+			}
+		}
 		else
 		{
 			cagg_parent = ts_continuous_agg_find_by_relid(rte->relid);
 
 			if (!cagg_parent)
 			{
+				ts_cache_release(hcache);
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("invalid continuous aggregate query"),
@@ -817,6 +834,7 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 
 			if (!ContinuousAggIsFinalized(cagg_parent))
 			{
+				ts_cache_release(hcache);
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("old format of continuous aggregate is not supported"),
@@ -827,7 +845,6 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 			}
 
 			parent_mat_hypertable_id = cagg_parent->data.mat_hypertable_id;
-			hcache = ts_hypertable_cache_pin();
 			ht = ts_hypertable_cache_get_entry_by_id(hcache, cagg_parent->data.mat_hypertable_id);
 
 			/* If parent cagg is hierarchical then we should get the matht otherwise the rawht. */
@@ -846,9 +863,12 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 		}
 
 		if (TS_HYPERTABLE_IS_INTERNAL_COMPRESSION_TABLE(ht))
+		{
+			ts_cache_release(hcache);
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("hypertable is an internal compressed hypertable")));
+		}
 
 		if (rte->relkind == RELKIND_RELATION)
 		{
@@ -861,6 +881,7 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 				const ContinuousAgg *cagg = ts_continuous_agg_find_by_mat_hypertable_id(ht->fd.id);
 				Assert(cagg != NULL);
 
+				ts_cache_release(hcache);
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("hypertable is a continuous aggregate materialization table"),
@@ -882,10 +903,13 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 		 *       below, along with any other fallout.
 		 */
 		if (part_dimension->partitioning != NULL)
+		{
+			ts_cache_release(hcache);
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("custom partitioning functions not supported"
 							" with continuous aggregates")));
+		}
 
 		if (IS_INTEGER_TYPE(ts_dimension_get_partition_type(part_dimension)) &&
 			rte->relkind == RELKIND_RELATION)
@@ -894,13 +918,16 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 			const char *funcname = NameStr(part_dimension->fd.integer_now_func);
 
 			if (strlen(funcschema) == 0 || strlen(funcname) == 0)
+			{
+				ts_cache_release(hcache);
 				ereport(ERROR,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("custom time function required on hypertable \"%s\"",
 								get_rel_name(ht->main_table_relid)),
 						 errdetail("An integer-based hypertable requires a custom time function to "
 								   "support continuous aggregates."),
 						 errhint("Set a custom time function on the hypertable.")));
+			}
 		}
 
 		caggtimebucketinfo_init(&bucket_info,
@@ -932,7 +959,10 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 		 * column of the hypertable
 		 */
 		Assert(query->groupClause);
-		caggtimebucket_validate(&bucket_info, query->groupClause, query->targetList);
+		caggtimebucket_validate(&bucket_info,
+								query->groupClause,
+								query->targetList,
+								is_cagg_create);
 	}
 
 	/* Check row security settings for the table. */
@@ -950,7 +980,8 @@ cagg_validate_query(const Query *query, const bool finalized, const char *cagg_s
 		Assert(prev_query->groupClause);
 		caggtimebucket_validate(&bucket_info_parent,
 								prev_query->groupClause,
-								prev_query->targetList);
+								prev_query->targetList,
+								is_cagg_create);
 
 		/* Cannot create cagg with fixed bucket on top of variable bucket. */
 		if ((bucket_info_parent.bucket_width == BUCKET_WIDTH_VARIABLE &&

tsl/src/continuous_aggs/common.h

@@ -3,6 +3,7 @@
  * Please see the included NOTICE for copyright information and
  * LICENSE-TIMESCALE for a copy of the license.
  */
+
 #ifndef TIMESCALEDB_TSL_CONTINUOUS_AGGS_COMMON_H
 #define TIMESCALEDB_TSL_CONTINUOUS_AGGS_COMMON_H
 
@@ -122,7 +123,8 @@ typedef struct AggPartCxt
 	} while (0);
 
 extern CAggTimebucketInfo cagg_validate_query(const Query *query, const bool finalized,
-											  const char *cagg_schema, const char *cagg_name);
+											  const char *cagg_schema, const char *cagg_name,
+											  const bool is_cagg_create);
 extern Query *destroy_union_query(Query *q);
 extern Oid relation_oid(Name schema, Name name);
 extern void RemoveRangeTableEntries(Query *query);
@@ -131,4 +133,5 @@ extern Query *build_union_query(CAggTimebucketInfo *tbinfo, int matpartcolno, Qu
 extern void mattablecolumninfo_init(MatTableColumnInfo *matcolinfo, List *grouplist);
 extern void mattablecolumninfo_addinternal(MatTableColumnInfo *matcolinfo);
 extern bool function_allowed_in_cagg_definition(Oid funcid);
-#endif
+
+#endif /* TIMESCALEDB_TSL_CONTINUOUS_AGGS_COMMON_H */

tsl/src/continuous_aggs/create.c

@@ -926,7 +926,8 @@ tsl_process_continuous_agg_viewstmt(Node *node, const char *query_string, void *
 	timebucket_exprinfo = cagg_validate_query((Query *) stmt->into->viewQuery,
 											  finalized,
 											  schema_name,
-											  stmt->into->rel->relname);
+											  stmt->into->rel->relname,
+											  true);
 	cagg_create(stmt, &viewstmt, (Query *) stmt->query, &timebucket_exprinfo, with_clause_options);
 
 	/* Insert the MIN of the time dimension type for the new watermark */
@@ -1024,7 +1025,8 @@ cagg_flip_realtime_view_definition(ContinuousAgg *agg, Hypertable *mat_ht)
 		cagg_validate_query(direct_query,
 							agg->data.finalized,
 							NameStr(agg->data.user_view_schema),
-							NameStr(agg->data.user_view_name));
+							NameStr(agg->data.user_view_name),
+							true);
 
 	/* Flip */
 	agg->data.materialized_only = !agg->data.materialized_only;

tsl/src/continuous_aggs/repair.c

@@ -112,7 +112,8 @@ cagg_rebuild_view_definition(ContinuousAgg *agg, Hypertable *mat_ht, bool force_
 		cagg_validate_query(direct_query,
 							finalized,
 							NameStr(agg->data.user_view_schema),
-							NameStr(agg->data.user_view_name));
+							NameStr(agg->data.user_view_name),
+							true);
 
 	mattablecolumninfo_init(&mattblinfo, copyObject(direct_query->groupClause));
 	fqi.finalized = finalized;