What are the types of database lock?

At the table level, there are five different types of locks:

  • Exclusive (X)
  • Shared (S)
  • Intent exclusive (IX)
  • Intent shared (IS)
  • Shared with intent exclusive (SIX)

What is lock type AE in Oracle?

■ the AE lock is an edition lock, available in oracle 11 g and above. It is part of the edition Based redefinition. feature (not covered in this particular book). ID1 is the object id of the edition that SID is using currently. this edition lock.

What is locked mode in Oracle?

This lock mode is used when a session needs exclusive access to part of a compound resource and shared access to the entire compound resource at the same time. These lock modes apply both to local locks and to the instance locks that are used between parallel server instances.

How many types of locking methods are there?

At the table level, there are 5 different types of locks. i.e, Exclusive (X), Shared (S), Intent exclusive (IX), Intent shared (IS), and Shared with intent exclusive (SIX) and these locks have already been discussed above. This type of locking level is not suitable for multi-user database management systems.

What are different types of locks in Oracle?

Oracle locks fall into one of three general categories. DML locks protect data. For example, table locks lock entire tables, row locks lock selected rows. DDL locks protect the structure of schema objects—for example, the definitions of tables and views.

What is V lock?

vlock is a utility used to lock one or several user virtual console sessions. vlock is important on a multi user system, it allows users to lock their own sessions while other users can still use the same system via other virtual consoles.

How many types of locks are there in Oracle?

What are the types of locks in Oracle?

What is locked mode 3?

The query against v$locked_object indicates that the table is locked in Locked Mode 3 (i.e. Row Exclusive Mode). Since the XIDUSN, XIDSLOT and XIDSQN are all 0 this indicates that no rows are actually locked. This can be confirmed by the query against v$lock.

What is shared and exclusive locks?

An exclusive or write lock gives a process exclusive access for writing to the specified part of the file. While a write lock is in place, no other process can lock that part of the file. A shared or read lock prohibits any other process from requesting a write lock on the specified part of the file.

What is ID1 and ID2 in V lock?

ID1 and ID2 -> There represents the rollback segment and transaction table entries for that transaction. So when session 1 acquired the lock it got rollback segment and transaction table entry.