DB2 connection definition attributes

The attributes are described in the categories:

General attributes

The general attributes of a DB2CONN are:

Name
The name to identify a DB2® connection definition. The name can be up to eight characters in length.
Description
(Optional.) Specifies a 1- to 30-character description of the resource.
Version
(Optional.) Specify an integer in the range 1 through 15. Specify 0 or leave blank for CICSPlex® SM to assign the first available version id in the range 1 through 15.
RESGROUP
(Optional.) Specify the name of an existing resource group to which the definition is to automatically added.
User data
(Optional.) Three 8-character fields provided for any site-specific data related to the connection. CICSPlex SM makes no use of this user data.

Connection attributes

The connection attributes of a DB2CONN are:

CONnecterror
Specifies the way that the information, that CICS® is not connected to DB2 because the attachment facility is in 'standby mode', is reported back to an application that has issued an SQL request.
ABEND
The application abends with abend code AEY9.
SQLCODE
The application receives a -923 sqlcode. SQLCODE cannot be specified if STANDBYMODE is set to NOCONNECT.
DB2Groupid
Specifies the group ID (up to four characters) of a data sharing group of DB2 subsystems. The group attach facility connects CICS to any active member of this data sharing group. If the DB2Groupid attribute is left blank, group attach is not used. You cannot specify both DB2Groupid and DB2ID.
DB2ID
Specifies the name of the DB2 subsystem to which the CICS DB2 attachment facility is to connect. By default this field is blank. The DB2ID set in the installed DB2CONN definition can be overridden by a DB2 subsystem ID specified on a DSNC STRT command, or by a DB2ID specified in a SET DB2CONN command. If the DB2ID in the installed DB2CONN definition is left blank, you can specify a DB2 subsystem ID on the INITPARM system initialization parameter. If no DB2 subsystem ID is specified by any of these means, the default DB2ID of blanks is replaced by DSN when the connection is attempted. Hence, the hierarchy for determining the DB2 subsystem is as follows:
  1. Use the subsystem ID if specified in a DSNC STRT command.
  2. Use the DB2ID in the installed DB2CONN if not blank.
  3. Use the subsystem ID if specified on the INITPARM when the DB2ID in the last installed DB2CONN is blank (or has subsequently been set to blanks). On any startup, INITPARM is always used if the last installed DB2CONN contained a blank DB2ID, even if the DB2ID was subsequently changed using a SET command.
  4. Use a default subsystem ID of DSN.
MSGQUEUE1
Specifies the first transient data destination to which unsolicited messages from the CICS DB2 attachment facility are sent. This first destination cannot be blank.
MSGQUEUE2
Specifies a second transient data destination to which unsolicited messages from the CICS DB2 attachment facility are sent.
MSGQUEUE3
Specifies a third transient data destination to which unsolicited messages from the CICS DB2 attachment facility are sent.
Nontermrel
Specifies whether or not a non-terminal transaction releases threads for reuse at intermediate syncpoints.
NO
Non-terminal transactions do not release threads for reuse at intermediate syncpoints.
YES
Non-terminal transactions release threads for reuse at intermediate syncpoints.
Purgecycle
Specifies the duration, in minutes and seconds, of the purge cycle for protected threads. The default is 0, 30; that is, 30 seconds.

A protected thread is not terminated immediately when it is released. It is terminated only after two completed purge cycles, if it has not been reused in the meantime. Therefore, if the purge cycle is set to 30 seconds, a protected thread is purged 30 - 60 seconds after it is released. The first purge cycle after the attachment facility starts is always 5 minutes. After that the purgecycle values are applied. An unprotected thread is terminated when it is released (at syncpoint or end of task) if there are no other transactions waiting for a thread on that DB2ENTRY. Only threads belonging to a DB2ENTRY can be protected. Pool threads and command threads cannot be protected.

Resyncmember
If you are using group attach, use the Resyncmember attribute to select the strategy that CICS adopts if outstanding units of work are being held for the last DB2 data sharing group member to which CICS was connected.
YES
indicates that if outstanding units of work are held, you require resynchronisation with the last DB2 data sharing group member to which CICS was connected. CICS ignores the group attach facility and waits until it can reconnect to that last connected DB2 data sharing group member, to resolve the indoubt units of work.
NO
indicates that you do not require resynchronisation. CICS makes one attempt to reconnect to the last connected DB2 data sharing group member. If this attempt is successful, the indoubt units of work can be resolved. If it is unsuccessful, then CICS uses group attach to connect to any active member of the DB2 data sharing group, and a warning message (DFHDB2064) is issued stating that there may be unresolved indoubt units of work with the last member of the group to which CICS was connected.
Signid
Specifies the authorization ID to be used by the CICS DB2 attachment facility when signing on to DB2 for pool and DB2ENTRY threads that specify AUTHTYPE(SIGN). The default is blanks which are replaced by the applid of the CICS system when the DB2CONN is installed.
Note:
If you specify a user ID on the SIGNID attribute, CICS performs a surrogate user check against the user ID performing the installation. Similarly, the CICS region user ID is subject to a surrogate user check during group list installation on a CICS cold or initial start.
STANbymode
Specifies the action to be taken by the CICS DB2 attachment facility if DB2 is not active when an attempt is made to connect CICS to DB2.
CONNECT
Specifies that the CICS DB2 attachment facility is to wait in ‘standbymode’ for DB2 to become active. If the connection is made, and DB2 subsequently fails, the CICS DB2 attachment facility terminates.
NOCONNECT
Specifies that the CICS DB2 attachment facility is to terminate.
RECONNECT
Specifies that the CICS DB2 attachment facility is to go into 'standby mode' and wait for DB2. If DB2 subsequently fails after the connection is made, the CICS DB2 attachment facility reverts to 'standby mode', and CICS subsequently reconnects to DB2 when DB2 recovers.
STATsqueue
Specifies the transient data destination for CICS DB2 attachment facility statistics produced when the CICS DB2 attachment facility is shut down.
TCblimit

Specifies the maximum number of TCBs that can be used to process DB2 requests. The default is 12. The minimum number is 4 and the maximum is 2000. When connected to DB2 Version 5 or earlier, the CICS DB2 attachment facility creates the TCBs in the form of subtasks up to the limit specified by TCBLIMIT. Each of these subtasks identifies to DB2 and creates a connection into DB2. When connected to DB2 Version 6 or later, CICS creates open TCBs (up to the limit specified by the system initialization parameter MAXOPENTCBS). The TCBLIMIT attribute of the DB2CONN definition governs how many of the open TCBs can be used to access DB2 -- that is, how many of them can identify to DB2 and create a connection into DB2.

The TCBLIMIT value controls the total number of threads for the CICS region. For this reason, the recommended value for TCBLIMIT is the sum of all the thread limit values (that is, the sum of all THREADLIMIT attributes on the DB2 connection and DB2 entry resource definitions, plus the COMTHREADLIMIT value on the DB2 connection definition) up to the limit of 2000. The value you choose for TCBLIMIT can be exceeded by increasing THREADLIMIT values for selected subtasks.

When determining the number for TCBLIMIT, you must consider the amount you specified for the MAX USERS parameter on DB2 installation panel DSNTIPE.

THREADError
Specifies the processing that is to occur following a create thread error.
ABEND
When the first SQL error is detected, CICS takes a transaction dump for abend code AD2S, AD2T, or AD2U, depending on the type of error. For the first error, the transaction does not abend. For a second or subsequent SQL error, the transaction abends with abend code AD2S, AD2T, or AD2U. The transaction must be terminated and reinitialized before it is allowed to issue another SQL request.
N906D
A transaction dump is to be taken and the DSNCSQL RMI associated with the transaction is not to be disabled. The transaction receives a -906 SQLCODE if another SQL is issued, unless the transaction issues SYNCPOINT ROLLBACK. SYNCPOINT without the ROLLBACK option results in an ASP3 or ASP7 abend. The transaction dump records an abend of AD2S, AD2T or AD2U.
N906
The DSNCSQL RMI associated with the transaction is not to be disabled. The transaction receives a -906 SQLCODE if another SQL request is issued, unless the transaction issues a SYNCPOINT ROLLBACK. SYNCPOINT without the ROLLBACK option results in an ASP3 or ASP7 abend.

Pool thread attributes

The pool thread attributes of a DB2CONN are:

ACcountrec
Specifies the minimum amount of DB2 accounting required for transactions using pool threads. The specified minimum may be exceeded as described in the following options.
NONE
No accounting records are required for transactions using pool threads.
TASK
The CICS DB2 attachment facility causes a minimum of one accounting record for each CICS task to be produced.
TXID
The CICS DB2 attachment facility causes an accounting record to be produced when the transid using the thread changes.
UOW
The CICS DB2 attachment facility causes an accounting record to be produced for each UOW, assuming that the thread is released at the end of the UOW.
AUTHid
Specifies the ID that should be used for security checking when using pool threads. If AUTHId is specified, AUTHTYPE may not be specified.
AUTHtype
Specifies the type of ID that can be used for threads on this DB2ENTRY. If AUTHTYPE is specified, AUTHID may not be specified.
USERID
The user ID associated with the CICS transaction is used as the authorization ID. If the user ID is less than eight characters in length, it is padded on the right with blanks.

When the DB2 sample sign-on exit DSN3@SGN is used with AUTHTYPE(USERID), the exit sends the user ID to DB2 as the primary authorization ID and the RACF® group ID to DB2 as the secondary ID. When the sample sign-on exit is used, there is no difference between AUTHTYPE(USERID) and AUTHTYPE(GROUP).

OPID
The operator identification that is associated with the userid that is associated with the CICS transaction is used as the authorization ID. The 3-character operator identification is padded on the right with blanks to form the 8-character authorization ID.
GROUP
Specifies the user ID and the connected group name as the authorization ID.

To use the GROUP option, the CICS system must have SEC=YES specified in the CICS system initialization table (SIT).

If no RACF group ID is available for this USERID, an 8-character field of blanks is passed to DB2 as the group ID.

SIGN
Specifies that the SIGNID attribute of the DB2 connection definition is to be used as the resource authorization ID.
TERM
Specifies the terminal identification as an authorization ID. The 4-character terminal identification is padded on the right with blanks to form the 8-character authorization ID.

If the transaction is not associated with a terminal (for example, if it is initiated with a START command), do not specify AUTHTYPE(TERM).

TX
Specifies the transaction identification as the authorization ID. The 4-character transaction identification is padded on the right with blanks to form the 8-character authorization ID.
DRollback
Specifies whether or not the CICS DB2 attachment facility should initiate a SYNCPOINT ROLLBACK if a transaction is selected as the victim of a deadlock resolution.
YES
The attachment facility issues a syncpoint rollback before returning control to the application. An SQL return code of -911 is returned to the program.

Do not specify YES if the pool is used by transactions running enterprise beans as part of an OTS transaction; CICS syncpoint rollback is not allowed in an OTS transaction. Consider defining a DB2ENTRY which specifies DROLLBACK(NO) for use by transactions which run enterprise beans as part of an OTS transaction.

NO
The attachment facility does not initiate a rollback for a transaction. An SQL return code of -913 is returned to the application.
PLAN
Specifies the name of the plan to be used for all pool threads. If PLAN is specified, PLANEXITNAME may not be specified.
PLANExitname
Specifies the name of the dynamic plan exit to be used for pool threads. If you change the PLAN and PLANEXITNAME while there are active transactions for the pool, the next time the transaction releases the thread the plan/exit will be determined using the new rules. If PLANEXITNAME is specified, PLAN may not be specified.
PRiority
Specifies the priority of the pool thread subtasks relative to the CICS main task (QR TCB). If CICS is connected to DB2 Version 6 or later, this setting is ignored, as the task runs on an open L8 TCB that has the same priority as the QR TCB. However, the priority value specified in the DB2CONN definition is still installed into the relevant control block, in case CICS connects to a lower level of DB2 at a later time.
HIGH
Subtasks attain a higher priority than the CICS main task from which the subtask was generated.
EQUAL
Subtasks have equal priority with the CICS main task.
LOW
Subtasks have a lower priority than the CICS main task.
THREADLimit
Specifies the current maximum number of pool threads that the CICS DB2 attachment facility allows to be active before requests are made to wait or are rejected (subject to the THREADWAIT attribute). The default threadlimit (3) is also the minimum you can specify. The maximum value must not be greater than the value specified for TCBLIMIT.
THREADWait
Specifies whether or not transactions should wait for a pool thread, or be abended if the number of active pool threads reaches the thread limit.

The CICS DB2 attachment issues a unique abend code AD3T, message DFHDB2011, when THREADWAIT=NO is coded and the number of pool threads is exceeded.

YES
If all threads are busy, a transaction must wait until one becomes available. A transaction can wait as long as CICS allows it to wait, generally until a thread becomes available.
NO
If all threads are busy, the transaction is terminated with abend code AD3T.

Command thread attributes

The DB2 connection definition command thread attribute descriptions are:

COMAUTHid
Specifies what id the CICS DB2 attachment facility should use for security checking when using command threads. If COMAUTHId is specified, COMAUTHType may not be specified.
COMAUTHType
Specifies the type of id that can be used for security checking when using command threads. If COMAUTHType is specified, COMAUTHid may not be specified.
USERID
The 1 to 8-character userid associated with the CICS transaction is used as the authorization ID. The name can be up to eight characters in length.

When the DB2 sample sign-on exit DSN3@SGN is used with AUTHTYPE(USERID), the exit sends the USERID to DB2 as the primary authorization ID and the RACF group ID to DB2 as the secondary ID. When the sample sign-on exit is used, there is no difference between COMAUTHTYPE(USERID) and COMAUTHTYPE(GROUP).

OPID
The operator identification associated with the userid that is associated with the CICS transaction sign-on facility is used as the authorization ID (three characters padded to eight).
GROUP
Specifies the 1 to 8-character USERID and the connected group name as the authorization ID.

To use the CGROUP option the CICS system must have SEC=YES specified in the CICS system initialization table (SIT).

If no RACF group ID is available for this USERID, an 8-character field of blanks is passed to DB2 as the group ID.

SIGN
Specifies that the SIGNID attribute of the DB2CONN is used as the resource authorization ID.
TERM
Specifies the terminal identification (four characters padded to eight) as an authorization ID. An authorization ID cannot be obtained in this manner if a terminal is not connected with the transaction.

If a transaction is started (using a CICS command) and has no terminal associated with it, the COMAUTHTYPE(TERM) should not be used.

TX
Specifies the transaction identification (four characters padded to eight) as the authorization ID.
COMThreadlim
The number specifies the current maximum number of command threads the CICS DB2 attachment facility allows active before requests overflow to the pool.

Related concepts
DB2 connection resource definitions
CICS Resource Definition Guide
Related tasks
Accessing BAS DB2 connection definitions
Working with the DB2CDEF view
Defining DB2 connections using BAS
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