add low_memory.xml for less clickhouse memory usage

docker-compose.yaml

@@ -20,6 +20,7 @@ services:
     volumes:
       - /var/log/clickhouse-server
       - ./docker/clickhouse/init_schema.sql:/docker-entrypoint-initdb.d/init_schema.sql
+      - ./docker/clickhouse/low_memory.xml:/etc/clickhouse-server/low_memory.xml
       - ./docker/clickhouse/postgres_dictionary.xml:/etc/clickhouse-server/postgres_dictionary.xml
       - ./docker/clickhouse/listen_ports.xml:/etc/clickhouse-server/config.d/listen_ports.xml
       - ./docker/clickhouse/ca-key.pem:/etc/clickhouse-server/ca-key.pem

docker/clickhouse/low_memory.xml

@@ -0,0 +1,34 @@
+<clickhouse>
+  <max_thread_pool_size>2000</max_thread_pool_size>
+  <merge_tree>
+    <merge_max_block_size>1024</merge_max_block_size>
+    <max_bytes_to_merge_at_max_space_in_pool>1073741824</max_bytes_to_merge_at_max_space_in_pool>
+    <number_of_free_entries_in_pool_to_lower_max_size_of_merge>0</number_of_free_entries_in_pool_to_lower_max_size_of_merge>
+    <number_of_free_entries_in_pool_to_execute_mutation>1</number_of_free_entries_in_pool_to_execute_mutation>
+    <number_of_free_entries_in_pool_to_execute_optimize_entire_partition>1</number_of_free_entries_in_pool_to_execute_optimize_entire_partition>
+  </merge_tree>
+
+  <mark_cache_size>268435456</mark_cache_size>
+  <index_mark_cache_size>67108864</index_mark_cache_size>
+  <uncompressed_cache_size>16777216</uncompressed_cache_size>
+  <mlock_executable>false</mlock_executable>
+
+  <max_connections>64</max_connections>
+  <max_concurrent_queries>8</max_concurrent_queries>
+  <max_server_memory_usage_to_ram_ratio>0.75</max_server_memory_usage_to_ram_ratio>
+
+  <background_buffer_flush_schedule_pool_size>1</background_buffer_flush_schedule_pool_size>
+  <background_pool_size>2</background_pool_size>
+  <background_merges_mutations_concurrency_ratio>2</background_merges_mutations_concurrency_ratio>
+  <background_merges_mutations_scheduling_policy>round_robin</background_merges_mutations_scheduling_policy>
+  <background_move_pool_size>1</background_move_pool_size>
+  <background_fetches_pool_size>1</background_fetches_pool_size>
+  <background_common_pool_size>2</background_common_pool_size>
+  <background_schedule_pool_size>8</background_schedule_pool_size>
+  <background_message_broker_schedule_pool_size>1</background_message_broker_schedule_pool_size>
+  <background_distributed_schedule_pool_size>1</background_distributed_schedule_pool_size>
+  <tables_loader_foreground_pool_size>0</tables_loader_foreground_pool_size>
+  <tables_loader_background_pool_size>0</tables_loader_background_pool_size>
+  <query_thread_log remove="1" />
+  <processors_profile_log remove="1" />
+</clickhouse>