A fix is available
APAR status
Closed as program error.
Error description
You receive message DFHIS1022 Protocol error (code X'061D') occurred on RECEIVE IPIC session in IPCONN ipconn. The connection error is due to no ISSBs being available to process incoming requests from CTG. The dumps indicate that CICS and CTG are out of step with their respective views of session availability. As soon as a mirror task sends its last response, CTG will assume that a session becomes available. The mirror task on CICS will try to free its receive session after sending this last response. However, the logic of freeing the session includes a call to user domain for function DELETE_USER. This requires the USADLOCK. If another task holds this lock and is stuck because of a bottleneck in the external security manager (ESM), then the freeing of the IPIC session ( ISSB) will get delayed. CTG believes that all these sessions are available so keeps sending new requests up to CICS. Eventually all the available sessions become allocated and the next CTG request for a given IPCONN will result in a DFHIS1023 message and an error response back to CTG. CICS uses the only system ISSB for the affected IPCONN to deliver this error response. If yet another request arrives while the system ISSB is in use then this gives rise to the DFHIS1022 and CICS will try to PURGE all mirror tasks associated with the affected IPCONN. If this happens CTG is forced to establish a new connection and create a new IPCONN. DFHISAL can be changed to defer the DELETE_USER call until after the ISSB is released to the free pool. This will ensure that any bottleneck in the ESM will not lead to a DFHIS1022 error. Additional Symptom(s) Search Keyword(s): MSGDFHIS1022 MSGDFHIS1023 KIXREVSLY
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All * **************************************************************** * PROBLEM DESCRIPTION: DFHIS1023 and DFHIS1022 can occur when * * there is a bottleneck in the external * * security manager. * **************************************************************** * RECOMMENDATION: * **************************************************************** A condition developed where the limit of available sessions for a CICS Transaction Gateway IPCONN was reached. At this point CTG stops sending further requests into CICS. Some mirror tasks owning these sessions now send their final responses to CTG and enter transaction termination. They call DFHISAL for function FREE_RECEIVE to release their sessions. DFHISAL calls DFHUSAD function DELETE_USER just before placing the session on the free chain. The DELETE_USER calls got held up due to a bottleneck in the external security manager. In this window CTG started sending new requests into CICS as sessions were now deemed to be available from its perspective. CICS is unable to allocate sessions for these new requests. This initially causes a DFHIS1023 conversation error with reason code 061D but can lead to a DFHIS1022 connection error with reason code 061D which causes the IPCONN to be released.
Problem conclusion
DFHISAL FREE_RECEIVE processing has been changed so that the DFHUSAD DELETE_USER call is deferred until after the ISSB ( IPCONN session ) has been placed on the free chain.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PM02642
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-12-03
Closed date
2010-01-06
Last modified date
2010-02-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK53287
Modules/Macros
DESISAL DFHISAL
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
R600 PSY UK53287
UP10/01/08 P F001
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 February 2010