Merge pull request #346 from Altinity/backport/23.8/57822_disable_system_kafka_consumers_table

23.8 Backport of ClickHouse#57822 - Disable `system.kafka_consumers` by default

Author: Enmk

src/Storages/Kafka/StorageKafka.cpp

@@ -660,10 +660,19 @@ void StorageKafka::updateConfiguration(cppkafka::Configuration & kafka_config,
 
     if (kafka_consumer_weak_ptr_ptr)
     {
+        /// NOTE: statistics should be consumed, otherwise it creates too much
+        /// entries in the queue, that leads to memory leak and slow shutdown.
+        ///
+        /// This is the case when you have kafka table but no SELECT from it or
+        /// materialized view attached.
+        ///
+        /// So for now it is disabled by default, until properly fixed.
+#if 0
         if (!config.has(config_prefix + "." + "statistics_interval_ms"))
         {
             kafka_config.set("statistics.interval.ms", "3000"); // every 3 seconds by default. set to 0 to disable.
         }
+#endif
 
         if (kafka_config.get("statistics.interval.ms") != "0")
         {