A fix is available
APAR status
Closed as program error.
Error description
When there is an insert and a delete in the same commit scope against a tablespace using page level locking, it is possible for DB2 to overload IRLM and XES with alter requests for the lock.
Local fix
Change the logic for DB2 to not send SET/INS on page level lock requests.
Problem summary
**************************************************************** * USERS AFFECTED: DB2 10 for z/OS users of * * segmented or UTS table space with page * * level locking. * **************************************************************** * PROBLEM DESCRIPTION: When an insert transaction requests * * a page lock, and the transaction * * already holds the lock from a prior * * delete, it will trigger IRLM to alter * * the lock from a delete type to an * * insert type. If the global lock * * manager is on a different member, this * * alter request can cause the coupling * * facility to reject the alter, which * * in turn causes IRLM to reject the page * * lock request. The INSERT then * * continues to request page locks, and * * subsequent inserts do the same. When * * there is a high volume of inserts * * following a delete in the same commit * * scope, it can result in high CPU in * * the IRLM and XCFAS address spaces. * * This problem can also happen when * * there is a high volume of DELETEs * * following an INSERT in the same commit * * scope. This only happens with page * * level locking. * **************************************************************** * RECOMMENDATION: * **************************************************************** The page lock request by the INSERT transaction can be falsely rejected when there is delete transaction already held a page lock on the same data page within the same commit scope. Under this circumstance, the page lock request by the INSERT transaction will trigger IRLM to alter or verify lock holding state with CF. As a result, high CPU in the IRLM and XCFAS address space can occurr when there is high volume of DELETE follow by INSERT within the same commit scope.
Problem conclusion
DB2 code is changed to avoid sending the alter requests which cause the coupling facility to falsely reject page lock requests.
Temporary fix
Comments
APAR Information
APAR number
PI29726
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
A10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2014-11-14
Closed date
2014-12-11
Last modified date
2015-01-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI23808
Modules/Macros
DSNISGRT
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RA10 PSY UI23808
UP14/12/30 P F412
Fix is available
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Document Information
Modified date:
06 May 2020