Skip to main contentIBM dmctop Wiki

Locking / Locks

Purpose

Locks view shows the list of locks in the currently connected database.

Screenshot

image

Metric shown

Grid

Locks held

The number of locks in the currently connected database.

SELECT COUNT(*) AS LOCKS_HELD 
FROM   TABLE(MON_GET_LOCKS(NULL, #MEMBER#))

Source: MON_GET_LOCKS

Agents waiting

The number of locks that each application’s agents (that are connected to the current database) are waiting to acquire.

SELECT COUNT(*) AS LOCKS_WAIT 
FROM   TABLE(MON_GET_APPL_LOCKWAIT(NULL, #MEMBER#))

Source: MON_GET_APPL_LOCKWAIT

Lock list storage %

The average number of locks per byte.

= LOCKS_HELD / LOCK_LIST_IN_USE_BYTES

LOCKS_HELD = 

SELECT COUNT(*) AS LOCKS_HELD 
FROM   TABLE(MON_GET_LOCKS(NULL, #MEMBER#))

Source:

LOCK_LIST_IN_USE_BYTES = MON_GET_DATABASE(#MEMBER#).SUM(LOCK_LIST_IN_USE)

MON_GET_LOCKS

Applications connected

The number of connections from the given database member.

SELECT COUNT(*) AS APPL_CONNECTED 
FROM   TABLE(MON_GET_CONNECTION(NULL, #MEMBER#))

Source: MON_GET_CONNECTION

Table

Application handle

A system-wide unique ID for the application.

Source: MON_GET_LOCKS(NULL,#MEMBER#).APPLICATION_HANDLE

Application name

The name of the application running at the client.

Source: MON_GET_AGENT(NULL,NULL,NULL,#MEMBER#).APPLICATION_NAME

Event state

State of the event last processed by this agent. The possible values are as follows:

  • EXECUTING
  • IDLE

Source: MON_GET_AGENT(NULL,NULL,NULL,#MEMBER#).EVENT_STATE

Event type

Type of event last processed by this agent. The possible values are as follows:

  • ACQUIRE
  • PROCESS
  • WAIT

Source: MON_GET_AGENT(NULL,NULL,NULL,#MEMBER#).EVENT_TYPE

Event object

Object of the event last processed by this agent. The possible values are as follows:

  • COMPRESSION_DICTIONARY_BUILD
  • IMPLICIT_REBIND
  • INDEX_RECREATE
  • LOCK
  • LOCK_ESCALATION
  • QP_QUEUE
  • REMOTE_REQUEST
  • REQUEST
  • ROUTINE
  • WLM_QUEUE

Source: MON_GET_AGENT(NULL,NULL,NULL,#MEMBER#).EVENT_OBJECT

Object name

The name of event object.

= <TABSCHEMA>.<TABNAME>

Source:

TABSCHEMA = MON_GET_TABLE(NULL,NULL, #MEMBER#).TABSCHEMA

TABNAME = MON_GET_TABLE(NULL,NULL, #MEMBER#).TABNAME

Lock mode

The type of lock being held.

Source: MON_GET_LOCKS(NULL,#MEMBER#).LOCK_MODE

Object type

The type of object against which the application holds a lock (for object-lock-level information), or the type of object for which the application is waiting to obtain a lock (for application-level and deadlock-level information).

Source: MON_GET_LOCKS(NULL,#MEMBER#).LOCK_OBJECT_TYPE

Lock status

The internal status of the lock.

Source: MON_GET_LOCKS(NULL,#MEMBER#).LOCK_STATUS

Lock count

The number of locks currently held.

Source: MON_GET_LOCKS(NULL,#MEMBER#).LOCK_COUNT

Is blocker

Flag (Yes or No) indicating whether the transaction holding this lock is itself blocked waiting on another lock.

Locked by

The application that is holding the lock.

If the LOCK_STATUS column is W or C, then get the application handle id of the first object from the lock list with LOCK_STATUS equals to G with given LOCK_NAME.

Source:

LOCK_STATUS = MON_GET_LOCKS(NULL,#MEMBER#).LOCK_STATUS

LOCK_NAME = MON_GET_LOCKS(NULL,#MEMBER#).LOCK_NAME

Tablespace name

The name of a table space.

Source: MON_GET_TABLESPACE.TBSP_NAME

Previous
Locking: Blockers, waiters
Next
Locking: Locked objects