IBMi - connect_cdc_mimix_share

Change Selector jobs running with OS/400 v7.4, require PTF #SI74644.

Customers running Change Selector jobs with OS/400 v7.4 must install PTF # [SI74644|https://www.ibm.com/support/pages/ptf/SI74644] to avoid a known issue for OS/400 v7.4 (SE74126) that prevents the SQL precompiler from running when SQL is embedded in some programs.

License Manager

If the License Manager is currently installed at version 6 or earlier you must upgrade to version 7 prior to upgrading to version 8.
The License Manager must be installed at version 8.0.15.00 or higher prior to installing the Change Selector.

System i5 TIMESTAMP Datatype Support

System i5, V7R2, supports the TIMESTAMP datatype with a fractional second precision from 6 to 12 digits. Connect CDC only supports a fractional second precision up to a maximum of 6 digits.

System i5 Change Selector capture does not access user source table, but during initialization a brief share lock is required

The System i5 Change Selector normally obtains all the information about a user table for which it is capturing data from the DB2 SQL catalog. This is all done at program initialization. However, during initialization there is a brief call to the system for each table where a share lock is required to obtain required metadata information about the table. This information is obtained by the following SQL calls: PREPARE and DESCRIBE.

If this information cannot be obtained, because some other process has an exclusive lock on the table, then the Change Selector stops.

Note: This is not a defect: obtaining this share lock to get metadata information is a requirement for proper operation of the program.

System i5 Change Selector job will not work correctly if submitted with CCSID 65535

If you submit a System i5 Change Selector job with the CCSID set to 65535, the Change Selector starts OK, but every attempt to register a table fails.

This problem will not occur if you run the Change Selector job with an IBM CCSID such as “37” or “n37” EBCDIC CCSID.

Create User Spaces for Change Selector

Connect CDC uses user spaces, file type *USRSPC. If your system restricts user spaces, the Connect CDC installation and metabase libraries must be added to the system variable QALWUSRDMN. Check the setting with “dspsysval qalwusrdmn”. Its value will be either *ALL or a list of libraries. If the value is a library list, the system administrator will need to add the installation and metabase libraries to this list after they are created.

Commitment Control and Numbers of Transactions

Connect CDC bundles updates into artificial transactions when commitment control is off. This may cause the number of transactions that Connect CDC MonCon reports to differ from what you might expect. DB2/400 self-commits updates, in which every row operation is treated as a transaction. This is the default behavior in DB2/400.

Replication with IBM i v5r3 and Higher

Due to a change in the way the IBM i v5r3 processes SQL DELETE statements without a WHERE clause, the delete is not written to the journal as a series of code R type DL records but instead with a sequence of code F and D records. Because of the way the journal records are written, the Connect CDC Change Selector is not able to capture this type of DELETE statement.

One way this new sequence of journal records can be generated is by a DELETE statement without a WHERE clause coded in a static SQL program, but note that there may be other types of delete of all records in an SQL table or file that result in the same sequence of journal records so this list is not all-inclusive.

Use Synchronization Request

On the Synchronization tab, during the synchronization’s copy phase, while the initial copy is ongoing, replication captures the data that is changing.

The Collision Resolution for this data (for v5.0.01.00), by default, is Target correct, ignore. Older models (versions prior to v5.0.01.00) will continue to use Source correct, fix as the default. Syncsort recommends that you use Target correct, ignore.

Refer to the Advanced User Guide “Chapter 7, Synchronization” for details on how to synchronize data.

IASP and SYSBAS

The i5 system prevents you from using the same name for a library in iASP and SYSBAS.

If you have already defined a metabase library name (for example, MXSHARE) in SYSBAS for a particular host, then you will not be allowed to define the same name when modeling the server as an iASP server on the same host.

If you use the same name, you will receive a message during the metabase installation stating that the library already exists. This is confusing since the library does not exist on the specified iASP.

There are two solutions to this issue:

If you want the library to be created on the iASP, change the name to one that does not exist on the host.
If possible, remove the metabase, then delete the library from SYSBAS and reinstall it on the iASP.

Note also, that due to restrictions imposed on exits by the i5 system, given the following situation:

A server in a model is defined with an associated iASP.
The metabase library resides on the iASP.
A journal and its receivers reside on SYSBAS.
The journal is defined in the Process Definition Properties Advanced page with “Receiver delete management” checked “Yes”.

There is currently a restriction that the Delete Receiver Exit (DRE) cannot properly manage receivers in a journal when the journal does not reside on the same ASP type (SYSBAS or iASP) as its metabase. In this case, receivers will not be deleted as expected. When the system attempts to delete any of the receivers associated with these journals, the DRE always returns the “NOT ELIGIBLE FOR DELETION” status.

Therefore, if you want the journal to be properly managed, the metabase library currently installed on the iASP, either needs to be removed from the iASP server and installed in SYSBAS, or the metabase library needs to be set to some other metabase library that currently resides on SYSBAS.

To address the previous restriction, in the case of a server in a model that is defined with an associated iASP, some additional checks have been added to the Director for the following situations:

If an Install metabase is attempted for a library that does not exist, the Director will display the following popup message:
- “Do you want the library installed on the iASP?”
If you click Yes, the library will be installed on the iASP. If you click No, the library will be installed on SYSBAS.
If the metabase library already exists on the iASP and there currently are delete managed journals that reside on SYSBAS, then the Director issues the following error message during model validation:
- “If you are planning to use the Delete Receiver Exit (DRE) program and define any of your journals in SYSBAS, Connect CDC requires that you install the metabase library in SYSBAS.”
In this case, do one of the following:
Remove the metabase in the Director, delete the library on the i5, and reinstall the metabase using the Director, which then will install it on SYSBAS.
Specify the name for a library that does not exist and then execute Install source metabase. This action causes Director to install the metabase on SYSBAS.
Set the “Receiver delete management” option to “No”.

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Connect CDC Release Notes