Communications link failure The last packet successfully received from the server was xxx milliseconds ago

## 环境信息

目标端 MySQL 8.0.22

## 同步千万数据时，1小时后出现错误

2022-06-22 23:06:06.632 [0-0-0-writer] WARN CommonRdbmsWriter$Task - 回滚此次写入, 采用每次写入一行方式提交. 因为:Communications link failure

The last packet successfully received from the server was 16,603 milliseconds ago. The last packet sent successfully to the server was 16,606 milliseconds ago.
2022-06-22 23:06:06.639 [0-0-0-writer] ERROR WriterRunner - Writer Runner Received Exceptions:
com.alibaba.datax.common.exception.DataXException: Code:[DBUtilErrorCode-05], Description:[往您配置的写入表中写入数据时失败.]. - java.sql.SQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknown.
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
at com.mysql.cj.jdbc.ConnectionImpl.rollback(ConnectionImpl.java:1859)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.doBatchInsert(CommonRdbmsWriter.java:360)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.startWriteWithConnection(CommonRdbmsWriter.java:293)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.startWrite(CommonRdbmsWriter.java:321)
at com.alibaba.datax.plugin.writer.mysqlwriter.MysqlWriter$Task.startWrite(MysqlWriter.java:78)
at com.alibaba.datax.core.taskgroup.runner.WriterRunner.run(WriterRunner.java:56)
at java.lang.Thread.run(Thread.java:748)
- java.sql.SQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknown.
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
at com.mysql.cj.jdbc.ConnectionImpl.rollback(ConnectionImpl.java:1859)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.doBatchInsert(CommonRdbmsWriter.java:360)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.startWriteWithConnection(CommonRdbmsWriter.java:293)
at com.alibaba.datax.plugin.rdbms.writer.CommonRdbmsWriter$Task.startWrite(CommonRdbmsWriter.java:321)
at com.alibaba.datax.plugin.writer.mysqlwriter.MysqlWriter$Task.startWrite(MysqlWriter.java:78)
at com.alibaba.datax.core.taskgroup.runner.WriterRunner.run(WriterRunner.java:56)
at java.lang.Thread.run(Thread.java:748)

Start with plugin/rdbmswriter/src/main/java/com/alibaba/datax/plugin/rdbmswriter/CommonRdbmsWriter.java around line 360, then trace MysqlWriter$Task and the MySQL connection handling in the stack trace. Reproduce the long-running sync against MySQL 8.0.22 and determine why rollback loses the connection after the reported interval. Done means the cause and a verified resolution or limitation are documented.

Written by the indexing model from the issue text.