Oracle 视图 V$HANG_INFO 官方解释，作用，如何使用详细说明

本站中文解释

本视图V$HANG_INFO由V$INSTANCE和V$BHANG两个子视图组成，主要的用途是报告挂起的会话的信息。V$HANG_INFO基于内部X$KGLH0和X$KGLH1两个表，用于保存和报告实例内正在挂起的会话信息。

使用V$HANG_INFO：

1.查询挂起的会话数量：select count(*) from v$hang_info;

2.查询挂起会话的唯一标识符：select distinct sid from v$hang_info;

3.查看挂起会话的诊断详细信息：select * from v$hang_info where sid=;

4.获得如何处理挂起会话的建议：select hang_advice from v$hang_info;

官方英文解释

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`^Foot 1	`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 Hang Manager 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

^Footnote 1This column is available starting with Oracle Database 21c.