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
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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