Does `SHOW PROCESSLIST` display the system process ID?

FAQ
1

The display content of TiDB SHOW PROCESSLIST is almost the same as that of MySQL SHOW PROCESSLIST. TiDB SHOW PROCESSLIST does not display the system process ID. The ID that it displays is the current session ID. The differences between TiDB SHOW PROCESSLIST and MySQL SHOW PROCESSLIST are as follows:

  • As TiDB is a distributed database, the tidb-server instance is a stateless engine for parsing and executing the SQL statements (for details, see TiDB architecture). SHOW PROCESSLIST displays the session list executed in the tidb-server instance that the user logs in to from the MySQL client, not the list of all the sessions running in the cluster. But MySQL is a standalone database and its SHOW PROCESSLIST displays all the SQL statements executed in MySQL.
  • The State column in TiDB is not continually updated during query execution. Because TiDB supports parallel query, each statement might be in multiple states at once, and so it is difficult to simplify to a single value.