Merge pull request #914 from Altinity/backports/25.3.6/79369

25.3.6 Backport of ClickHouse#79369 -- Ignore parse error in system.distributed_ddl_queue

Author: zvonand

src/Storages/System/StorageSystemDDLWorkerQueue.cpp

@@ -29,6 +29,11 @@ namespace Setting
     extern const SettingsUInt64 max_query_size;
 }
 
+namespace ErrorCodes
+{
+    extern const int SYNTAX_ERROR;
+}
+
 enum class Status : uint8_t
 {
     INACTIVE,
@@ -62,7 +67,7 @@ ColumnsDescription StorageSystemDDLWorkerQueue::getColumnsDescription()
         {"entry_version",       std::make_shared<DataTypeNullable>(std::make_shared<DataTypeUInt8>()), "Version of the entry."},
         {"initiator_host",      std::make_shared<DataTypeNullable>(std::make_shared<DataTypeString>()), "Host that initiated the DDL operation."},
         {"initiator_port",      std::make_shared<DataTypeNullable>(std::make_shared<DataTypeUInt16>()), "Port used by the initiator."},
-        {"cluster",             std::make_shared<DataTypeString>(), "Cluster name."},
+        {"cluster",             std::make_shared<DataTypeString>(), "Cluster name, empty if not determined."},
         {"query",               std::make_shared<DataTypeString>(), "Query executed."},
         {"settings",            std::make_shared<DataTypeMap>(std::make_shared<DataTypeString>(), std::make_shared<DataTypeString>()), "Settings used in the DDL operation."},
         {"query_create_time",   std::make_shared<DataTypeDateTime>(), "Query created time."},
@@ -85,8 +90,23 @@ static String clusterNameFromDDLQuery(ContextPtr context, const DDLTask & task)
 
     String description = fmt::format("from {}", task.entry_path);
     ParserQuery parser_query(end, settings[Setting::allow_settings_after_format_in_insert]);
-    ASTPtr query = parseQuery(
-        parser_query, begin, end, description, settings[Setting::max_query_size], settings[Setting::max_parser_depth], settings[Setting::max_parser_backtracks]);
+    ASTPtr query;
+
+    try
+    {
+        query = parseQuery(
+            parser_query, begin, end, description, settings[Setting::max_query_size], settings[Setting::max_parser_depth], settings[Setting::max_parser_backtracks]);
+    }
+    catch (const Exception & e)
+    {
+        LOG_INFO(getLogger("StorageSystemDDLWorkerQueue"), "Failed to determine cluster");
+        if (e.code() == ErrorCodes::SYNTAX_ERROR)
+        {
+            /// ignore parse error and present available information
+            return "";
+        }
+        throw;
+    }
 
     String cluster_name;
     if (const auto * query_on_cluster = dynamic_cast<const ASTQueryWithOnCluster *>(query.get()))