MAXLOCKS—Maximum number of locks

Use the Modify Maximum Number of Locks panel or the MAXLOCKS command to specify new maximum values for locks per user and locks per table space (or locks per table, for segmented table spaces).

Modify Maximum Number of Locks panel

DDTAMML 1+ Modify Maximum Number of Locks
Command ===> _________________________________________________________________

 Command: CURRENT
Description . . . . . . . . : MAX LOCKS PER TABLE SPACE/USER

Type the new maximum number of locks values that you wish to change to. Then press Enter.

Maximum Number of Locks Parameters
Max per table(space) . . . . __________ (0-104857600 or delta)
Max per user . . . . . . . . __________ (0-104857600 or delta)

MAXLOCKS per user is the maximum number of locks an application can hold against all table spaces in the system. If the maximum is reached, Db2 terminates the thread. The IRLM needs 128–256 bytes per lock. If the number of locks per user is increased, the value takes effect immediately.

Warning

If this value is decreased below the current number of locks a user holds, the next request for a lock by that user will be denied, and the thread will be terminated abnormally.

MAXLOCKS per table space applies only to tables defined with LOCKSIZE ANY and is the maximum number of locks an application can hold against a single table space before lock escalation occurs.

If you increase the number of locks per table space, the value takes effect immediately (applies only to LOCKSIZE ANY). If this value is decreased below the current number of locks outstanding for a table space, the next request for a lock on this table space causes lock escalation.

Command syntax and parameters

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Value

Description

DB2ssid

Db2 subsystem ID or the name of the Db2 data sharing group to which the command applies.

opertuneID

OPERTUNE system profile name (if OPERTUNE is running as a started task) or the batch job name (if OPERTUNE is running as a batch job).

tableLocks

Maximum number of locks an application can hold against a table or table space before lock escalation occurs. Specify one of the following values:

  • 0—locks are not counted and no escalation occurs (not recommended)
  • A numerical value in the range 1–104857600
  • A delta value
    Delta values are expressed numerically (+nn or -nn) or as a percentage (+nn% or -nn%). The resulting value must fall in the range 0–104857600*.

userLocks

Maximum number of locks an application can hold across all table spaces in the system. Specify one of the following values:

  • 0—no limit to the number of locks a program can acquire (not recommended)
  • A numerical value in the range 1–104857600.
    For Db2 version 7.1, this range is 1–2097152.
  • A delta value
    Delta values are expressed numerically (+nn or -nn) or as a percentage (+nn% or -nn%). The resulting value must fall in the range 0–104857600.

NORESET

The changes you request remain in effect until the Db2 subsystem is cycled.

Db2 parameter values

Field

Installation panel

CLIST parameter

ZPARM macro

ZPARM parameter

Max per table(space)

DSNTIPJ

IRLMLKTS

DSN6SPRM

NUMLKTS

Max per user

DSNTIPJ

IRLMLKUS

DSN6SPRM

NUMLKTS

 

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