How to identify table locking situations in Oracle database

In Oracle database, table locking is a common database operation situation. When a session is operating a certain table, if another session also wants to operate the same table , table locking will occur. Table locking may cause database performance to degrade, or even cause deadlocks and other problems. Therefore, timely identification and resolution of table locking situations is critical to ensuring the normal operation of the database.

In the Oracle database, you can identify table locking situations by querying Oracle's data dictionary view. The following are some commonly used query code examples to help identify table locking conditions:

1. Query the locking conditions in the current database session:

SELECT   a.object_id,
         c.object_name,
         a.sid,
         a.serial#,
         a.status,
         a.osuser,
         a.process,
         a.lockwait,
         a.lockwait_time
FROM     v$locked_object a, dba_objects c
WHERE    a.object_id = c.object_id;

The above query will list the current database The object being locked includes information such as object ID, object name, session ID, session serial number, session status, operating system user, process ID, and status waiting for locking.

2. Query the locked tables in the current database:

SELECT   b.owner,
         b.object_name,
         b.object_type,
         c.sid,
         d.serial#,
         c.serial#,
         c.lockwait
FROM     v$locked_object a,
         dba_objects b,
         v$session c,
         v$process d
WHERE    a.object_id = b.object_id
AND      a.session_id = c.sid
AND      c.paddr = d.addr;

The above query will list the locked table names, table types and session related lock tables in the current database. Information, including session ID, session serial number, lock waiting status, etc.

The above query code examples can help the database administrator understand the table locking situation in the database in a timely manner, and then take corresponding measures to solve the table locking problem and ensure the normal operation of the database. However, when identifying table locking situations, care needs to be taken to avoid misoperations that may affect the database.

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