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  2. Dynamic Performance Views
  3. Dynamic Performance (V$) Views: V$ACCESS to V$HVMASTER_INFO
  4. V$HANG_INFO

8.276 V$HANG_INFO

V$HANG_INFO displays information about hangs found on the cluster.

A hang can be an open wait chain or closed wait chain (cycle or deadlock). A wait chain is a series of sessions that are blocking one another. Each row represents a hang and describes how severe the hang is. This view also includes the victim or final blocker of the hang.

Column Datatype Description

HANG_ID

NUMBER

A number identifying the hang

HANG_CHAIN_SESSIONS

NUMBER

Indicates how many sessions are in the main wait chain of the hang

TOTAL_HUNG_SESSIONS

NUMBER

Indicates how many total sessions are affected by the hang, including the main wait chain and any wait chains branching off of the main wait chain

HANG_TYPE

VARCHAR2(18)

Is set to Hang if this is an open wait chain or Deadlock if this is a cycle or closed wait chain

HANG_STATUS

VARCHAR2(20)

Status of the hang. Possible values:

  • Invalid - The hang is about to be removed because its hung status has become in doubt
  • Pending Resolution - The hang or deadlock has been marked for resolution and will be resolved shortly
  • Reconfiguration - A reconfiguration occurred and the hang or deadlock must be re-detected and verified before any action can be taken toward resolution
  • Requires Verification - The hang is about to be verified to confirm if its sessions are still hung
  • Resolved - The hang or deadlock was resolved by terminating the final blocker (or root) or, if necessary, by terminating the instance
  • Self-Resolved - The hang was detected but resolved on its own without Blocker Resolver intervention
  • Unresolvable - The hang was determined to be a special case that is not resolvable
  • Valid - The hang or deadlock was detected but not yet verified
  • Verified Hung - The hang has been verified and a decision will be made soon on whether the hang will be resolved or ignored
  • Victim Selected - A victim has been selected. If the hang is marked for resolution, the victim will be terminated.

HANG_CREATE_TIME

VARCHAR2(20)

Date and time that the hang was detected

HANG_RESOLVE_TIME

VARCHAR2(20)

Time that the hang may be automatically resolved

IGNORED_HANG

VARCHAR2(1)

Y - Hang was ignored and will not be automatically resolved at this time

N - The hang has not yet been verified

RESOLUTION_ATTEMPTED

VARCHAR2(1)

Y - An attempt was made to resolve the hang

N - No attempt was made to resolve the hang

GLOBAL_HANG

VARCHAR2(1)

Y - The hang spans multiple nodes in the cluster

N - All of the sessions in the hang reside on a single instance

ESCALATED_HANG

VARCHAR2(1)

Y - An attempt was made to resolve the hang but was unsuccessful, and the hang is becoming more severe. Another resolution attempt will be made.

N - The first resolution attempt was successful and it was not necessary to escalate the hang to a higher resolution level.

RESOLUTION_STATUS

VARCHAR2(45)

Contains the reason why the hang was resolved or ignored

VICTIM_INSTANCE

NUMBER

Instance number of the instance on which the victim or final blocker session resides

VICTIM_SESSION_ID

NUMBER

Victim or final blocker's Oracle session ID

VICTIM_SERIAL#

NUMBER

Victim or final blocker's Oracle session serial number

VICTIM_OSPID

VARCHAR2(24)

Victim or final blocker's operating system process ID

FATAL_BACKGROUND

VARCHAR2(1)

Y - Victim or final blocker is a critical background process

N - Victim or final blocker is not a critical background process

PNAME

VARCHAR2(5)

Name of the victim or final blocker process

VICTIM_PDB_ID

NUMBER

Victim or final blocker's container ID or PDB ID

WAIT_EVENT_TEXT

VARCHAR2(64)

Resource or event for which the victim or final blocker is waiting; set to not in a wait if the session is not waiting on a resource

VICTIM_QOS_PC_RANK

VARCHAR2(12)

Oracle Database Quality of Service (QoS) Management Performance Class rank of the victim or final blocker of the hang.

VICTIM_QOS_PC_ITT

NUMBER

Oracle Database QoS Management Performance Class In-Trouble Threshold of the victim or final blocker of the hang

VICTIM_QOS_PC_RTT

NUMBER

Oracle Database QoS Management Performance Class Root Termination allowed Threshold of the victim or final blocker of the hang

VICTIM_QOS_PC_KEY

NUMBER

Oracle Database QoS Management Performance Class Key of the victim or final blocker of the hang

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

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