DATASTORE statement
The DATASTORE statement defines a connection to the OTMA component of an IMS data store. You can specify multiple DATASTORE statements or omit the DATASTORE statement if this IMS Connect instance does not communicate with OTMA.
IMS Connect does not enforce a limit on the number of DATASTORE statements that you can define. Resource supply and consumption, which vary depending on the configuration of your subsystems, your operating environments, and your workloads, could possibly limit the number of active data store connections that you can use at any one time; however, you are unlikely to hit that limit because IMS Connect control blocks are relatively small and can extend into extended private storage (EPVT). A degradation in performance is likely to occur before any resource-imposed limit is reached.
Another potential limit could be imposed by your z/OS® cross-system coupling facility (XCF) configuration. An XCF group has a limit to the number of XCF members that it can support. Each data store connection is treated by XCF as a separate member and an XCF group also contains non-IMS Connect members, such as IMS or IBM® MQ. Therefore, the number of XCF members and the number of XCF groups that you define, as well as your XCF workload, could limit the number of data store connections that you can define.
For more information about XCF groups, see z/OS MVS™ Setting Up a Sysplex.
You can also create data store definitions dynamically with the CREATE IMSCON TYPE(DATASTORE) type-2 command.
DATASTORE statement syntax
DATASTORE statement parameters
- ACKTO=
- Specifies a timeout interval for
acknowledgements to OTMA for CM0 and CM1 output messages and for IMS-to-IMS transaction
messages.
The timeout value can be from 0 to 255 seconds. If the timeout value is 0 or is not specified, the OTMA ACK timeout default value of 120 seconds is set.
For IMS-to-IMS transaction messages, if an acknowledgement is not received by OTMA before the timeout interval expires, OTMA reroutes the transaction message to the default timeout queue, DFS$$TOQ.
- APPL=
- A 1- to 8-character alphanumeric TCP/IP APPL name defined to RACF® in the PTKTDATA statement.
This parameter is optional and defaults to blanks. If you are using
PassTicket and user message exits, you must specify the APPL on the
DATASTORE statement.
The APPL name is passed to RACF whether or not a PassTicket is actually used, and therefore can be used to verify a user's authority to access the datastore.
- CASCADE=
- For this data store connection only,
enables or disables support for the cascading of
global, two-phase commit (synclevel=syncpoint)
z/OS Resource Recovery Services transactions from IMS TM Resource Adapter via a TCP/IP connection to an IMS TM or IMS DB/DC system
that is on a different z/OS image (LPAR) than IMS Connect.
Cascading transactions that are received via a LOCAL
option connection is not supported.
The CASCADE parameter applies only to the support for cascading global, RRS transactions between IMS Connect and IMS TM when they are on different z/OS images. The specification of the IMS Connect CASCADE parameter does not affect support between other components or subsystems, such as between IMS subsystems in a shared queues environment.
The CASCADE specification in the definition of a data store connection overrides the value of CASCADE that is in effect for the IMS Connect system.
Until the next restart of IMS Connect, a CASCADE specification made by the UPDATE IMSCON TYPE(DATASTORE) SET(CASCADE()) command overrides the CASCADE specification on the DATASTORE configuration statement.
- CM0ATOQ
- 1- to 8-character name of the OTMA CM0 ACK timeout queue. The value specified here overrides both the OTMA default value of DFS$$TOQ and any value set on the HWS statement.
- DRU=
- A 1- to 8-character alphanumeric DRU keyword. The DRU keyword enables you to specify your own OTMA destination resolution user exit name that is to be passed to OTMA. The DRU exit is required to support asynchronous output to IMS Connect clients. The default is DFSYDRU0, but you can write your own exit.
- GROUP=
- The z/OS cross-system coupling facility group name for the IMS OTMA. IMS Connect uses this value to join one or more XCF groups. Because IMS Connect and IMS must be in the same XCF group in order to communicate, this group name must match the XCF group name that you define to IMS (GRNAME) in the IMS startup JCL (for example, "OTMA=Y,GRNAME=&GROUP,USERVAR=&MEMBER",...). Each IMS Connect can join any number of groups.
- ID=
- The data store name, which:
- Consists of alphanumeric character data
- Begins with an alphabetic character
- Has a length between 1 byte and 8 bytes
- Is unique within the IMS Connect configuration member
This ID must match the data store ID that is supplied by the client. For IMS TM Resource Adapter clients, this ID must match the name that is specified in the IMS Interaction Spec for IMS TM Resource Adapter. For non-IMS TM Resource Adapter clients, the ID must match the data store ID that is placed in the IMS Request Message (IRM) that is sent to IMS Connect.Restriction: The name specified on the ID parameter cannot be the same as a name specified on the TMEMBER parameter of any IMSPLEX statement or substatement in the HWSCFGxx member of the IMS PROCLIB data set. - MAXI=
- Specifies the OTMA input message flood control value in the IMS Connect configuration file. The valid range is from 0 to 9999. If you do not specify a value, or specify a value of 0, the OTMA default value of 5000 is used. If you specify a value between 1 and 200, the OTMA minimum value of 200 is used. If you specify a value greater than 9999, the OTMA maximum value of 9999 is used. If you specify a value less than zero or greater than 65 535, abend U3401 is issued.
- MEMBER=
- The XCF member name that identifies IMS Connect in the XCF group specified by the GROUP parameter. This name is the XCF name that IMS uses to communicate with IMS Connect in that XCF group. This XCF member name for IMS Connect must be unique in the data store definitions for all data stores that are members of the same XCF group.
- MULTIRTP=
- Specifies the OTMA tpipe support for the parallel processing of
multiple RESUME TPIPE requests (MULTIRTP) for the data store connection
that is defined by this DATASTORE statement.
The MULTIRTP specification on the DATASTORE statement overrides any MULTIRTP specification on the HWS statement. If the MULTIRTP parameter is not specified on the DATASTORE statement, the DATASTORE connection inherits the MULTIRTP specification from the HWS statement or, if MULTIRTP is not specified on the HWS statement, from OTMA.
- N
- Specifies that this data store connection requires an OTMA tpipe that supports only a single active RESUME TPIPE request. Output messages on the TPIPE are sent serially.
- Y
- Specifies that this data store connection requires an OTMA tpipe that supports multiple active RESUME TPIPE requests in parallel. When a tpipe has multiple active RESUME TPIPE requests from multiple DATASTORE connections, OTMA sends the callout or CM0 output messages on the first available connection that is in a receive state.
- #
- Specifies that MULTIRTP support for this data store connection is determined by the MULTIRTP value in effect for OTMA.
- OAAV=
- A decimal integer that defines the OTMA accessor environment element (ACEE) aging value, in seconds, for the data store that is specified by the ID keyword. When the OTMA ACEE aging value is reached, OTMA refreshes the ACEE before it processes the next input message received from IMS Connect. Valid values are from 0 to 999999. The default is 999999 seconds. If you specify 0, OTMA uses the default value. If you specify a value from 1 to 300, OTMA uses a value of 300 seconds. OTMA requires a value of at least 300 to enable ACEE refreshes.
- RRNAME=
- The name of an alternate destination specified in a client reroute request. If this string is not provided, IMS Connect uses HWS$DEF as the default name. The string is terminated by any blank or invalid character. The reroute name is truncated at any invalid character. This value must be a string of 1- to 8-uppercase alphanumeric (A - Z, 0 - 9) or special characters (@, #, $), left-aligned, and padded with blanks. IMS Connect translates lowercase characters to uppercase characters.
- SENDALTP=
- Specifies whether the ALTPCB output that is initiated by a commit-then-send send-receive
transaction needs to be sent back to the origin client of this data store. If the
DATASTORE statement does not specify the SENDALTP
parameter, the default value is # and the connection inherits the SENDALTP
specification from OTMA.
- N
- Specifies that IMS keeps the ALTPCB output to this data store in a tpipe hold queue. The ALTPCB output can be retrieved by a RESUME TPIPE request.
- Y
- Specifies that IMS sends the ALTPCB output that is initiated by an IMS Connect commit-then-send send-receive call back to the originating IMS Connect client. If the ALTPCB output cannot be sent, the output is saved in a tpipe hold queue or is removed when asked.
- #
- Specified that the SENDALTP support for this data store connection is determined by the SENDALTP value in the OTMA client descriptor.
- SMEMBER=
- 1 - 4 alphanumeric character field that specifies the name of the OTMA super member to which this DATASTORE belongs. If specified on the DATASTORE statement, this value overrides the value of the SMEMBER parameter specified on the HWS statement. To disable the value of SMEMBER= specified on DATASTORE, use SMEMBER=####.
- TMEMBER=
- The XCF member name for IMS that IMS Connect uses in order to communicate with an IMS in its XCF group. This target member name must match the member name IMS uses when it joins the XCF group. The XCF member name for IMS is specified in the IMS startup JCL (for example, "...,OTMA=Y,GRNAME=&GROUP, OTMANM=&TMEMBER,...").