mysql是单进程多线程模式, 所以看到的是线程号(所以你猜猜thread是啥意思?).
使用ps的话, 得加个-T (Show threads, possibly with SPID column)才行, 也就是 ps -efT |grep -i 3220
例子:

(root@127.0.0.1) [db1]> select * from performance_schema.threads order by THREAD_OS_ID desc limit 1\G
*************************** 1. row ***************************
          THREAD_ID: 51
               NAME: thread/sql/one_connection
               TYPE: FOREGROUND
     PROCESSLIST_ID: 8
   PROCESSLIST_USER: root
   PROCESSLIST_HOST: localhost
     PROCESSLIST_DB: db1
PROCESSLIST_COMMAND: Query
   PROCESSLIST_TIME: 0
  PROCESSLIST_STATE: executing
   PROCESSLIST_INFO: select * from performance_schema.threads order by THREAD_OS_ID desc limit 1
   PARENT_THREAD_ID: 1
               ROLE: NULL
       INSTRUMENTED: YES
            HISTORY: YES
    CONNECTION_TYPE: SSL/TLS
       THREAD_OS_ID: 3735
     RESOURCE_GROUP: USR_default
1 row in set (0.00 sec)

(root@127.0.0.1) [db1]> system ps -efT | grep 3735
mysql      2490   3735   1466  0 09:32 ?        00:00:00 /soft/mysql_3314/mysqlbase/mysql/bin/mysqld --defaults-file=/data/mysql_3314/conf/mysql_3314.cnf --basedir=/soft/mysql_3314/mysqlbase/mysql --datadir=/data/mysql_3314/mysqldata --plugin-dir=/soft/mysql_3314/mysqlbase/mysql/lib/plugin --user=mysql --log-error=/data/mysql_3314/mysqllog/dblogs/mysql3314.err --open-files-limit=123456 --pid-file=/data/mysql_3314/run/mysql.pid --socket=/data/mysql_3314/run/mysql.sock --port=3314
root       6555   6555   3734  0 10:25 pts/2    00:00:00 sh -c  ps -efT | grep 3735
root       6557   6557   6555  0 10:25 pts/2    00:00:00 grep 3735
(root@127.0.0.1) [db1]>