A fix is available
APAR status
Closed as program error.
Error description
Db2 may stop using I/O buffering when reading forward on a multi-volume archive log dataset on disk. The part of the archive log dataset that is on the first volume will use buffering, but parts on other volumes will not. This can affect log read I/O performance of Db2 archive logs reads of multi-volume archive log datasets on disk, when the log is read in a forward manner, such as reading the log via IFI 306 requests, or during the log apply phase of the RECOVER utility (except for the backout part if that is needed). This does NOT apply to archive logs on tape, nor compressed archive logs on disk.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All Db2 for z/OS users. * **************************************************************** * PROBLEM DESCRIPTION: Slower archive log read may be * * encountered when the Db2 archive log is * * a multi-volume (DASD) data set. This * * performance issue may happen in IFI * * read, RECOVER, or any utility reading * * the archive logs in a forward * * direction. * **************************************************************** * RECOMMENDATION: Apply corrective PTF when available. * **************************************************************** When reading logs from the second or subsequent volume of a multi-volume archive log data set on DASD, log manager switches to single buffer read. Db2 uses multiple buffer reads for reading logs on the first volume. The switching may affect the log read performance. The performance degradation is only applicable to archive log read in forward direction. The problem is not applicable to archives which are striped data sets, compressed data sets, single volume data sets, or on tape.
Problem conclusion
The code is fixed by resetting the single buffer read control flag when accessing the second or subsequent volume of the archive log set.
Temporary fix
Comments
APAR Information
APAR number
PH07227
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
B10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-01-16
Closed date
2019-02-15
Last modified date
2019-03-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI61329 UI61330
Modules/Macros
DSNJR008
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
01 March 2019