openxs@ao756:~/dbs/8.0$ bin/mysql --socket=/tmp/mariadb105.sock performance_schema

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 16

Server version: 5.5.5-10.5.6-MariaDB Source distribution

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> flush tables with read lock;

Query OK, 0 rows affected (0.00 sec)

mysql> select * from metadata_locks\G

*************************** 1. row ***************************

          OBJECT_TYPE: BACKUP

        OBJECT_SCHEMA: NULL

          OBJECT_NAME: NULL

OBJECT_INSTANCE_BEGIN: 140032711161584

            LOCK_TYPE: BACKUP_FTWRL1

        LOCK_DURATION: EXPLICIT

          LOCK_STATUS: GRANTED

               SOURCE:

      OWNER_THREAD_ID: 41

       OWNER_EVENT_ID: 1

*************************** 2. row ***************************

          OBJECT_TYPE: TABLE

        OBJECT_SCHEMA: performance_schema

          OBJECT_NAME: metadata_locks

OBJECT_INSTANCE_BEGIN: 140032711207584

            LOCK_TYPE: SHARED_READ

        LOCK_DURATION: TRANSACTION

          LOCK_STATUS: GRANTED

               SOURCE:

      OWNER_THREAD_ID: 41

       OWNER_EVENT_ID: 1

2 rows in set (0.00 sec)

openxs@ao756:~/dbs/8.0$ bin/mysql --socket=/tmp/mysql8.sock -uroot performance_schema

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 9

Server version: 8.0.21 Source distribution

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> flush tables with read lock;

Query OK, 0 rows affected (0.00 sec)

mysql> select * from metadata_locks\G

*************************** 1. row ***************************

          OBJECT_TYPE: GLOBAL

        OBJECT_SCHEMA: NULL

          OBJECT_NAME: NULL

          COLUMN_NAME: NULL

OBJECT_INSTANCE_BEGIN: 139972652157040

            LOCK_TYPE: SHARED

        LOCK_DURATION: EXPLICIT

          LOCK_STATUS: GRANTED

               SOURCE: lock.cc:1033

      OWNER_THREAD_ID: 50

       OWNER_EVENT_ID: 112

*************************** 2. row ***************************

          OBJECT_TYPE: COMMIT

        OBJECT_SCHEMA: NULL

          OBJECT_NAME: NULL

          COLUMN_NAME: NULL

OBJECT_INSTANCE_BEGIN: 139972651632368

            LOCK_TYPE: SHARED

        LOCK_DURATION: EXPLICIT

          LOCK_STATUS: GRANTED

               SOURCE: lock.cc:1108

      OWNER_THREAD_ID: 50

       OWNER_EVENT_ID: 112

...