A fix is available
APAR status
Closed as program error.
Error description
When experiencing a short-on-storage condition, you may receive message: EYUCT0105E Transport Services control block shortage has occurred. (Note that the EYUCT0105E message can occur at other times, including valid usage.) . CTMB failed with an exception setting trace pointID 4 CMPI_SCPT_NOTSPBLK in the ACQUIRE_TSPBLK routine. PointID 4 is is set if the TRNSPT_FTSPP queue is zeros. In the COM's MOEB at x'458' TRNSPT_FTSPP is 00000000 FF86897D which says we are out of Transport blocks. . During this time the MAS is SOS so there are several CTRC trace entries with a tpid of 17 indicating an error getting storage. When this occurs, we exit without freeing the CTSB back to the free pool.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICSPlex/SM V3R1M0 Users * **************************************************************** * PROBLEM DESCRIPTION: Various communications errors may occur * * due to an orphaning of Transport * * services control blocks (EYURCTSB), * * when a CMAS or MAS experiences a short- * * on-storage (SOS) condition in EDSA. * * * * When this occurs, the CMAS or MAS will * * issue message EYUCT0105E. Examination * * of the region's auxtrace dataset will * * show exception trace records issued by * * method EYU0CTRC (CTRC) that have a * * trace point ID of 17 and a debug text * * of "EXCEPT". * * * * Please note that a CMAS or MAS may * * experience temporary shortages of * * EYURCTSB control blocks based upon * * activity within the region. When this * * occurs, message EYUCT0105E will be * * issued, but the CMAS or MAS will not * * experience an SOS condition in EDSA, * * and CTRC will not issue the exception * * trace records noted above. When this * * occurs, please refer to the * * documentation for message EYUCT0105E * * regarding tuning suggestions. * **************************************************************** * RECOMMENDATION: After applying the PTF that resolves this * * APAR, all CMASes and MASes must be * * restarted. Note that the restarts do not * * need to occur at the same time. * **************************************************************** When method EYU0CTRC (CTRC) is called to perform cleanup of a completed communication request, it calls method EYU0XLML (XLML) to retrieve METAMFLD records associated with the request's parameter list (method argument list - MAL). Since CTRC does not know how many METAMFLD records are associated with the MAL, it passes a buffer to XLML that would allow it to return 100 records on a single call. Since this area is too large to be part of the normal working (STAK) storage for CTRC, a CICS GETMAIN is issued for the storage area. If the GETMAIN request fails because the CMAS or MAS is SOS, CTRC fails the cleanup request, and does not free up the EYURCTSB associated with the communication request. Depending upon how long the SOS condition exists, this could result in all EYURCTSB control blocks being orphaned. When this occurs, the CMAS or MAS can neither issue nor receive communications requests with other CMASes and MASes. In addition to orphaning EYURCTSB blocks when an SOS condition occurs in EDSA, the practice of issuing a GETMAIN request whenever cleanup is performed for a completed communications request results in unnecessary overhead. Methods EYU0CTST (CTST) and EYU0CTRP (CTRP) perform similar GETMAIN requests when communications requests between CMASes are sent (CTST) or received (CTRP), adding to this overhead.
Problem conclusion
To reduce the overhead and remove the EDSA SOS orphaning risk, the following changes have been made: - XLML and its MAL (EYUZXLML) have been updated to allow its caller to request a specific number of METAMFLD elements, specifying a starting ID of the first METAMFLD to be returned. - Callers of XLML for METAMFLDs have been updated to request at most 10 elements on a call to XLML. The storage for these elements is now reserved in the caller's STAK, removing the requirement for the CICS GETMAIN. Since limiting the caller to receiving 10 METAMFLD elements at a time could result in a caller requiring multiple calls to XLML for a single request, other operands have been specified in the calls to XLML to limit the type of METAMFLD records being returned to match exactly what the caller requires. As a result, most requests are satisfied with a single call to XLML. CTRC and CTRP have been updated to use this new method to call XLML. CTST, which did not use the METAMFLD records itself, but instead passed them to method EYU0CTSD (CTSD), has been updated to remove its call to XLML. This has now been moved to CTSD. Finally methods EYU0CTED (CTED) and EYU0CTER (CTER), which handle sends (CTED) and receives (CTER) between a CAMS and MAS, have been updated also.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
Various communications errors may occur due to an orphaning of Transport services control blocks (EYURCTSB), when a CMAS or MAS experiences a short- on-storage (SOS) condition in EDSA. When this occurs, the CMAS or MAS will issue message EYUCT0105E. Examination of the region's auxtrace dataset will show exception trace records issued by method EYU0CTRC (CTRC) that have a trace point ID of 17 and a debug text of "EXCEPT". Please note that a CMAS or MAS may experience temporary shortages of EYURCTSB control blocks based upon activity within the region. When this occurs, message EYUCT0105E will be issued, but the CMAS or MAS will not experience an SOS condition in EDSA, and CTRC will not issue the exception trace records noted above. When this occurs, please refer to the documentation for message EYUCT0105E regarding tuning suggestions. When method EYU0CTRC (CTRC) is called to perform cleanup of a completed communication request, it calls method EYU0XLML (XLML) to retrieve METAMFLD records associated with the request's parameter list (method argument list - MAL). Since CTRC does not know how many METAMFLD records are associated with the MAL, it passes a buffer to XLML that would allow it to return 100 records on a single call. Since this area is too large to be part of the normal working (STAK) storage for CTRC, a CICS GETMAIN is issued for the storage area. If the GETMAIN request fails because the CMAS or MAS is SOS, CTRC fails the cleanup request, and does not free up the EYURCTSB associated with the communication request. Depending upon how long the SOS condition exists, this could result in all EYURCTSB control blocks being orphaned. When this occurs, the CMAS or MAS can neither issue nor receive communications requests with other CMASes and MASes. In addition to orphaning EYURCTSB blocks when an SOS condition occurs in EDSA, the practice of issuing a GETMAIN request whenever cleanup is performed for a completed communications request results in unnecessary overhead. Methods EYU0CTST (CTST) and EYU0CTRP (CTRP) perform similar GETMAIN requests when communications requests between CMASes are sent (CTST) or received (CTRP), adding to this overhead. To reduce the overhead and remove the EDSA SOS orphaning risk, the following changes have been made: - XLML and its MAL (EYUZXLML) have been updated to allow its caller to request a specific number of METAMFLD elements, specifying a starting ID of the first METAMFLD to be returned. - Callers of XLML for METAMFLDs have been updated to request at most 10 elements on a call to XLML. The storage for these elements is now reserved in the caller's STAK, removing the requirement for the CICS GETMAIN. Since limiting the caller to receiving 10 METAMFLD elements at a time could result in a caller requiring multiple calls to XLML for a single request, other operands have been specified in the calls to XLML to limit the type of METAMFLD records being returned to match exactly what the caller requires. As a result, most requests are satisfied with a single call to XLML. CTRC and CTRP have been updated to use this new method to call XLML. CTST, which did not use the METAMFLD records itself, but instead passed them to method EYU0CTSD (CTSD), has been updated to remove its call to XLML. This has now been moved to CTSD. Finally methods EYU0CTED (CTED) and EYU0CTER (CTER), which handle sends (CTED) and receives (CTER) between a CAMS and MAS, have been updated also.
APAR Information
APAR number
PK43973
Reported component name
CPSM CICS 3.1
Reported component ID
5655M1501
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2007-04-25
Closed date
2007-05-23
Last modified date
2007-06-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK25392 PK45718
Modules/Macros
DYU0XLML EYUQXLML EYURCOEB EYURCTSR EYURXLML EYURXLWA EYUTRKNL EYUYXLML EYUZXLML EYU0CTED EYU0CTER EYU0CTRC EYU0CTRP EYU0CTSD EYU0CTST EYU0XLML EYU9XLPU EYU9XLP3 EYU9XLP4 EYU9XLP5 EYU9XLP6
Fix information
Fixed component name
CPSM CICS 3.1
Fixed component ID
5655M1501
Applicable component levels
R100 PSY UK25392
UP07/05/25 P F705
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:
22 February 2023