为提高效率，提问时请提供以下信息，问题描述清晰可优先响应。
- 【TiDB 版本】：2.1.14
- 【问题描述】：执行Update 语句 出现Lost connection to MySQL server during query错误，select语句正常，每执行一次tidb节点就down掉一个。
以下是收集的日志信息：
{‘tidb_log_dir’: ‘{{ deploy_dir }}/log’, ‘dummy’: None, ‘tidb_port’: 4000, ‘tidb_status_port’: 10080, ‘tidb_cert_dir’: ‘{{ deploy_dir }}/conf/ssl’}
系统信息
+-----------------+----------------------------+
| Host | Release |
+-----------------+----------------------------+
| jiesuan_tidb_01 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan_tidb_02 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan-tikv-01 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan-tikv-02 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan-tikv-03 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan-tikv-04 | 3.10.0-862.14.4.el7.x86_64 |
| pump_145 | 3.10.0-862.14.4.el7.x86_64 |
| pump_146 | 3.10.0-862.14.4.el7.x86_64 |
| pump_147 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan_monitor | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan_pd-01 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan_pd-02 | 3.10.0-862.14.4.el7.x86_64 |
| jiesuan_pd-03 | 3.10.0-862.14.4.el7.x86_64 |
+-----------------+----------------------------+
TiDB 集群信息
+---------------------+--------------+------+----+------+
| TiDB_version | Clu_replicas | TiDB | PD | TiKV |
+---------------------+--------------+------+----+------+
| 5.7.25-TiDB-v2.1.14 | 3 | 5 | 3 | 4 |
+---------------------+--------------+------+----+------+
集群节点信息
+-------------+-------------+
| Node_IP | Server_info |
+-------------+-------------+
| instance_11 | pd |
| instance_0 | tikv |
| instance_1 | tidb |
| instance_2 | pd |
| instance_4 | tidb |
| instance_5 | tikv |
| instance_6 | tidb |
| instance_7 | tidb |
| instance_8 | pd |
| instance_9 | tidb |
| instance_10 | tikv |
| instance_3 | tikv |
+-------------+-------------+
容量 & region 数量
+---------------------+-----------------+--------------+
| Storage_capacity_GB | Storage_uesd_GB | Region_count |
+---------------------+-----------------+--------------+
| 7039.25 | 533.84 | 140553 |
+---------------------+-----------------+--------------+
QPS
+---------+----------------+-----------------+
| Clu_QPS | Duration_99_MS | Duration_999_MS |
+---------+----------------+-----------------+
| 1.58 | 241.92 | 4.00 |
+---------+----------------+-----------------+
热点 region 信息
+---------------+----------+-----------+
| Store | Hot_read | Hot_write |
+---------------+----------+-----------+
| store-store_5 | 1 | 0 |
| store-store_4 | 1 | 0 |
| store-store_6 | 1 | 0 |
| store-store_1 | 0 | 0 |
+---------------+----------+-----------+
磁盘延迟信息
+--------+----------+-------------+--------------+
| Device | Instance | Read_lat_MS | Write_lat_MS |
+--------+----------+-------------+--------------+
+--------+----------+-------------+--------------+
若提问为**性能优化、故障排查**类问题，请下载<a href="/uploads/short-url/uGisshjxFnxx1KgpFOYbfeZjsc6" download="info_gathering.py">脚本</a>运行。终端输出的打印结果，请**务必全选**并复制粘贴上传。