Set allow_remote_fs_zero_copy_replication to true by default

src/Storages/MergeTree/MergeTreeSettings.h

@@ -124,7 +124,7 @@ struct Settings;
     M(UInt64, concurrent_part_removal_threshold, 100, "Activate concurrent part removal (see 'max_part_removal_threads') only if the number of inactive data parts is at least this.", 0) \
     M(String, storage_policy, "default", "Name of storage disk policy", 0) \
     M(Bool, allow_nullable_key, false, "Allow Nullable types as primary keys.", 0) \
-    M(Bool, allow_remote_fs_zero_copy_replication, false, "Allow Zero-copy replication over remote fs", 0) \
+    M(Bool, allow_remote_fs_zero_copy_replication, true, "Allow Zero-copy replication over remote fs", 0) \
     M(Bool, remove_empty_parts, true, "Remove empty parts after they were pruned by TTL, mutation, or collapsing merge algorithm", 0) \
     M(Bool, assign_part_uuids, false, "Generate UUIDs for parts. Before enabling check that all replicas support new format.", 0) \
     M(Int64, max_partitions_to_read, -1, "Limit the max number of partitions that can be accessed in one query. <= 0 means unlimited. This setting is the default that can be overridden by the query-level setting with the same name.", 0) \

src/Storages/MergeTree/ReplicatedMergeTreeMergeStrategyPicker.cpp

@@ -144,9 +144,14 @@ void ReplicatedMergeTreeMergeStrategyPicker::refreshState()
 
     if (current_replica_index_tmp < 0 || active_replicas_tmp.size() < 2)
     {
-        LOG_WARNING(storage.log, "Can't find current replica in the active replicas list, or too few active replicas to use execute_merges_on_single_replica_time_threshold!");
+        if (execute_merges_on_single_replica_time_threshold > 0)
-        /// we can reset the settings w/o lock (it's atomic)
+        {
-        execute_merges_on_single_replica_time_threshold = 0;
+            LOG_WARNING(storage.log, "Can't find current replica in the active replicas list, or too few active replicas to use execute_merges_on_single_replica_time_threshold!");
+            /// we can reset the settings w/o lock (it's atomic)
+            execute_merges_on_single_replica_time_threshold = 0;
+        }
+        /// default value of remote_fs_execute_merges_on_single_replica_time_threshold is not 0
+        /// so we write no warning in log here
         remote_fs_execute_merges_on_single_replica_time_threshold = 0;
         return;
     }

tests/integration/test_replicated_merge_tree_hdfs_zero_copy/configs/config.d/storage_conf.xml

@@ -59,7 +59,6 @@
     <merge_tree>
         <min_bytes_for_wide_part>1024000</min_bytes_for_wide_part>
         <old_parts_lifetime>1</old_parts_lifetime>
-        <allow_remote_fs_zero_copy_replication>1</allow_remote_fs_zero_copy_replication>
     </merge_tree>
 
     <remote_servers>

tests/integration/test_replicated_merge_tree_s3_zero_copy/configs/config.d/storage_conf.xml

@@ -21,7 +21,6 @@
 
     <merge_tree>
         <min_bytes_for_wide_part>0</min_bytes_for_wide_part>
-        <allow_remote_fs_zero_copy_replication>1</allow_remote_fs_zero_copy_replication>
     </merge_tree>
 
     <remote_servers>

tests/integration/test_s3_zero_copy_replication/configs/config.d/s3.xml

@@ -66,7 +66,6 @@
     <merge_tree>
         <min_bytes_for_wide_part>1024</min_bytes_for_wide_part>
         <old_parts_lifetime>1</old_parts_lifetime>
-        <allow_remote_fs_zero_copy_replication>1</allow_remote_fs_zero_copy_replication>
     </merge_tree>
 
     <remote_servers>

tests/queries/0_stateless/01700_system_zookeeper_path_in.reference

@@ -12,3 +12,5 @@ blocks
 failed_parts
 last_part
 parallel
+shared
+shared