2.1.5集群，扩容集群后，balance较慢，pending tablets 全部卡在decommission 阶段
"schedule_slot_num_per_hdd_path"="8"
balance_slot_num_per_path = 4
主要的调优手段有哪些呢
MySQL [(none)]> SHOW PROC '/cluster_balance/pending_tablets';
+-----------+--------+--------+-----------+---------+----------------------+----------+-------+---------+--------+----------+---------+---------------------+---------------------+---------------------+----------+-------------+------+-------------+---------------+------------+--------+--------------------------------------------------------------+
| TabletId | Type | Medium | Status | State | SchedCode | Priority | SrcBe | SrcPath | DestBe | DestPath | Timeout | Create | LstSched | LstVisit | Finished | ReplicaSize | Rate | FailedSched | FailedRunning | VisibleVer | CmtVer | ErrMsg |
+-----------+--------+--------+-----------+---------+----------------------+----------+-------+---------+--------+----------+---------+---------------------+---------------------+---------------------+----------+-------------+------+-------------+---------------+------------+--------+--------------------------------------------------------------+
| 90188323 | REPAIR | HDD | REDUNDANT | PENDING | WAITING_DECOMMISSION | NORMAL | -1 | -1 | -1 | -1 | 0 | 2026-03-17 20:06:07 | 2026-03-17 20:11:23 | 2026-03-17 20:11:23 | NULL | 233.449 MB | NULL | 0 | 0 | 501 | 501 | wait txn before post watermark txn 226595841 to be finished |
| 98508934 | REPAIR | HDD | REDUNDANT | PENDING | WAITING_DECOMMISSION | NORMAL | -1 | -1 | -1 | -1 | 0 | 2026-03-17 20:05:06 | 2026-03-17 20:11:23 | 2026-03-17 20:11:23 | NULL | 48.100 MB | NULL | 0 | 0 | 126 | 126 | wait txn before post watermark txn 226595850 to be finished |
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