A fix is available
APAR status
Closed as program error.
Error description
DFSISTS0 processing will become very slow when processing long chains of message switched transactions and may appear to be looping. In the supplied SLDS file, some Type x'03' records show very high message switch counts, such as... . Field Value Description -------- ------ ------------------------------------------ MSGPREFI 65,535 NO. OF PGM-PGM MSG SWITCHES TO GET TO THIS INPUT . TRAN : WQSESB LOG Sequence Number : 00000000020BAD8F - Many records show values over 60,000. - With a sufficient number of these long chains, it may not be possible to run DFSISTS0 with some SLDS files.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All IMS V12 users. * **************************************************************** * PROBLEM DESCRIPTION: DFSISTS0 takes a very long time to * * complete when processing a log with * * a high number of program switches * * * **************************************************************** * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF * **************************************************************** DFSISTS0 builds a tree to represent message and transaction events recorded by the input log file. Program switches are included in the tree as nodes, so logs with high numbers of program switches result in very large trees. The number of nodes between the root of the tree and a leaf node can become extremely large. DFSISTS0 was leaving the tree intact throughout the time required to process the entire input log, so the tree keeps growing as DFSISTS0 works through the log data. Because the tree was being traversed constantly as it grew, the time required to reach destination nodes was increasing dramatically. At times, it could appear that DFSISTS0 was looping because so much calculation was required to find nodes in the tree.
Problem conclusion
GEN: KEYWORDS: *** END IMS KEYWORDS *** DFSISTS0 now maintains the internal tree differently. Stastics are generated from tree nodes as the log is being consumed. Once the required information has been pulled from the input log and statistics can be generated for a particular node, the tree can be pruned by removing nodes that are no longer needed. DFSISTS0 continues collecting statistics and pruning nodes until all input data has been read. This prevents the tree from becoming so large that it significantly hurts performance.
Temporary fix
Comments
APAR Information
APAR number
PM93934
Reported component name
IMS V12
Reported component ID
5635A0300
Reported release
200
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-07-26
Closed date
2013-10-03
Last modified date
2013-11-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK98211
Modules/Macros
DFSISTS0
Fix information
Fixed component name
IMS V12
Fixed component ID
5635A0300
Applicable component levels
R200 PSY UK98211
UP13/10/08 P F310
Fix is available
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Document Information
Modified date:
14 December 2020