The Clone Plugin Setting a global system variable runtime value normally requires the  SYSTEM_VARIABLES_ADMIN privilege (or the deprecated  SUPER  privilege). For more information, see Section 5.1.9.1, “System Variable Privileges” . Clone variables are configured on the recipient MySQL server instance where the cloning operation is executed. When  clone_autotune_concurrency  is enabled (the default), additional threads for remote cloning operations are spawned dynamically to optimize data transfer speed. The setting is applicable to recipient MySQL server instance only. During a cloning operation, the number of threads increases incrementally toward a target of double the current thread count. The effect on the data transfer speed is evaluated at each increment. The process either continues or stops according to the following rules: The autotuning process does not support decreasing the number of threads. The  clone_max_concurrency  variable defines the maximum number of threads that can be spawned. If  clone_autotune_concurrency  is disabled,  clone_max_concurrency  defines the number of threads spawned for a remote cloning operation. 1129 Command-Line Format --clone-buffer-size Introduced 8.0.17 System Variable clone_buffer_size Scope Global Dynamic Yes •If there is at least a 25% improvement after reaching the target, the process continues toward a new target of double the current thread count. Otherwise, the process stops. •If there is at least a 10% improvement after reaching 50% of the target, the process continues. Otherwise, the process stops. •If there is at least a 5% improvement after reaching 25% of the target, the process continues. Otherwise, the process stops. •If the data transfer speed degrades more than 5% with an incremental increase, the process stops. Command-Line Format --clone-autotune-concurrency Introduced 8.0.17 System Variable clone_autotune_concurrency Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Boolean Default Value ON • clone_autotune_concurrency • clone_buffer_size