Merge remote-tracking branch 'altinity/25.6/settings_update_lock_object_storage_task_distribution_ms' into bugfix/antalya-25.6.5/lock_object_storage_task_distribution_ms_lost_host

Author: ianton-ru

src/Core/Settings.cpp

@@ -6891,8 +6891,18 @@ Cache the list of objects returned by list objects calls in object storage
     DECLARE(Bool, distributed_plan_optimize_exchanges, true, R"(
 Removes unnecessary exchanges in distributed query plan. Disable it for debugging.
 )", 0) \
-    DECLARE(UInt64, lock_object_storage_task_distribution_ms, 0, R"(
-In object storage distribution queries do not distibute tasks on non-prefetched nodes until prefetched node is active.
+    DECLARE(UInt64, lock_object_storage_task_distribution_ms, 500, R"(
+In object storage distribution queries do not distribute tasks on non-prefetched nodes until prefetched node is active.
+Determines how long the free executor node (one that finished processing all of it assigned tasks) should wait before "stealing" tasks from queue of currently busy executor nodes.
+
+Possible values:
+
+- 0  - steal tasks immediately after freeing up.
+- >0 - wait for specified period of time before stealing tasks.
+
+Having this `>0` helps with cache reuse and might improve overall query time.
+Because busy node might have warmed-up caches for this specific task, while free node needs to fetch lots of data from S3.
+Which might take longer than just waiting for the busy node and generate extra traffic.
 )", EXPERIMENTAL) \
     DECLARE(String, distributed_plan_force_exchange_kind, "", R"(
 Force specified kind of Exchange operators between distributed query stages.

src/Core/SettingsChangesHistory.cpp

@@ -67,7 +67,11 @@ const VersionToSettingsChangesMap & getSettingsChangesHistory()
         /// controls new feature and it's 'true' by default, use 'false' as previous_value).
         /// It's used to implement `compatibility` setting (see https://github.com/ClickHouse/ClickHouse/issues/35972)
         /// Note: please check if the key already exists to prevent duplicate entries.
-        addSettingsChanges(settings_changes_history, "25.6.5.2000",
+        addSettingsChanges(settings_changes_history, "25.6.5.20364",
+        {
+            {"lock_object_storage_task_distribution_ms", 500, 500, "Raised the value to 500 to avoid hoping tasks between executors."},
+        });
+        addSettingsChanges(settings_changes_history, "25.6.5.20000",
         {
             {"allow_experimental_database_iceberg", false, true, "Turned ON by default for Antalya"},
             {"allow_experimental_database_unity_catalog", false, true, "Turned ON by default for Antalya"},