V$SESSION_BLOCKERS

V$SESSION_BLOCKERS displays the blocker sessions for each blocked session. Each row represents a blocked and blocker session pair. If a session is blocked by multiple sessions there will be multiple rows for that blocked session. The maximum number of blocker sessions displayed for a single blocked session is 30. If a session is not blocked by other sessions, then there will be no row in this view for that session.

Column Datatype Description

SID

NUMBER

Blocked session's Oracle session identifier

SESS_SERIAL#

NUMBER

Blocked session's Oracle session serial number

WAIT_ID

NUMBER

A number identifying the wait for the blocked session

WAIT_EVENT

NUMBER

Resource or event number for which the blocked session is waiting

WAIT_EVENT_TEXT

VARCHAR2(64)

Resource or event for which the blocked session is waiting

BLOCKER_INSTANCE_ID

NUMBER

Blocker session's instance identifier

BLOCKER_SID

NUMBER

Blocker session's Oracle session identifier

BLOCKER_SESS_SERIAL#

NUMBER

Blocker session's Oracle session serial number

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data