Corrupted DDM/DRDA parse table symptoms and resolution

Troubleshooting

Problem

Application requester "Systemi_1" is trying to make a DRDA connection to Application Server "Systemi_2". This fails with message SQ30020.

Symptom

Application requester "Systemi_1" is trying to make a DRDA connection to Application Server "Systemi_2" and fails with message SQ30020 on the client/AR side:

Message . . . . :   Distributed Relational Database Architecture (DRDA) protocol error.                                        
Cause . . . . . :   Command or SQL statement failed due to a distribution protocol error that will affect subsequent SQL statements or commands.
The application has been disconnected and the process is in an unconnected state. The protocol error is X'1254' with a location code of X'01'.
The location codes are: -- '01'X -- The error was detected at the application requester.                                
 '1245'X -- Conversation protocol error.

The QRWTSRVR job on server/AS side may contain errors:

CPF3E80   40   01/08/20  12:34:54.965318  QCNTEDDM     QSYS        *STMT    QRWTSR     QSYS
      From user . . . . . . . . . :  <USR_PRF>  
      From module . . . . . . . . :  QCNTEDDM 
      From procedure . . . . . . :  SNDMSG 
      Statement . . . . . . . . . :  8815
      To module . . . . . . . . . :  QRWTSRVR
      To procedure . . . . . . . :  main
      Statement . . . . . . . . . :  337
      Message . . . . :  Syntax error detected in DDM datastream.

Or:

CPF9150   40   06/21/20  01:09:41.715003  QCNXDLL      QSYS        *STMT    QCNTDLL     QSYS
      From module . . . . . . . . :   QCNXPRSE                                        
      From procedure  . . . . . . :   QCNXPrse                                        
      Statement . . . . . . . . . :   3011                                            
      To module . . . . . . . . . :   QCNTRCV                                         
      To procedure  . . . . . . . :   PRSEDATA                                        
      Statement . . . . . . . . . :   3804                                            
      Message . . . . :   Message sent internally by CN.                              
      Technical description . . . . . . . . :   This message is used internally by    
        the CN component to ensure cleanup is done by the various layers during       
        error situations.

Cause

The DDM/DRDA parse table "QCNPRSTBLS" has become corrupted.

Resolving The Problem

Save the damaged object in a SAVF in the event later diagnosis is warranted:

CRTSAVF FILE(DMGPRSTBL)
SAVOBJ OBJ(QCNPRSTBLS) LIB(QSYS) DEV(*SAVF) SAVF(DMGPRSTBL)

Next, delete the corrupted parse table on the Application server:

DLTOBJ OBJ(QSYS/QCNPRSTBLS) OBJTYPE(*USRSPC)

The object is re-created when a new request is received by the DDM server. The error(s) should no longer occur.

In other instances, deleting the parse table QSYS/QCNPRSTBLS on the Application requester resolved the issue.

Example error message from an Application requester client source machine which suffered a power outage:

CPF3E01    Diag 40   11/30/21  14:42:43.844931  QCNSMCTL 
      From module . . . . . . . . :   QCNSMCTL      
      From procedure  . . . . . . :   QCNSMCTL      
      Statement . . . . . . . . . :   3613          
      To module . . . . . . . . . :   ToModule      
      To procedure  . . . . . . . :   ToProcedure   
      Statement . . . . . . . . . :   1500          
      Message . . . . :   DDM parameter value not supported. 
      Cause . . . . . :   A value was sent from the client that is not supported by 
        this server. The following are not supported (See X'1443'): -- '1144'X or

The above was also resolved by deleting the parse table.

If the parse table object is repeatedly becoming corrupt, please contact IBM i Support.

Related Information

IBM Support

[{"Business Unit":{"code":"BU070","label":"IBM Infrastructure"},"Product":{"code":"SWG60","label":"IBM i"},"ARM Category":[{"code":"a8m0z0000000CRKAA2","label":"Data Access-\u003EDDM DRDA"}],"ARM Case Number":"","Platform":[{"code":"PF012","label":"IBM i"}],"Version":"All Version(s)","Line of Business":{"code":"LOB68","label":"Power HW"}}]

Historical Number

479384977

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Document Information

Modified date:
02 May 2024

UID

nas8N1013836

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