IBM Integrated Synchronization

Compatibility

You need not remove existing CDC implementations as long as they serve different Db2 subsystems. A single accelerator can be the common replication target of different Db2 subsystems using either CDC or IBM Integrated Synchronization. However, this type of setup is not recommended.

Feature prerequisites

To use IBM Integrated Synchronization, you need:

• One of the following database management systems:
  • Db2 12 for z/OS with the latest fix for APAR PH06628 (PTF UI63356 at the time of this writing) installed, running at function level V12R1M500.
  • Db2 13 for z/OS

  You can retrieve a list of all recommended fixes from the Prerequisites and Maintenance website.

• Distributed data facility (DDF) with a secure port, configured for network encryption through AT-TLS
• For data sharing groups: ability to always connect to the same member using one of the following options:
  • A member-specific secure port that has a local alias
  • The high-availability setup for data sharing groups by means of DDVIPA and the TIMEDAFFINITY option. See Suggestion for a high-availability setup.
• IBM Db2 Analytics Accelerator for z/OS Version 7.5.0 or later.

Prerequisites for tables and hints

• Tables to be included must have a unique constraint (primary key or primary index). If such a key does not exist in the accelerator-shadow table or cannot be determined, you must redefine the table and specify such a key. You cannot do this from IBM Db2 Analytics Accelerator Studio; you must run the corresponding stored procedure (SYSPROC.ACCEL_ADD_TABLES) with a special option. The columns that you choose for the key must contain unique values or form such values when they are combined. The values of the selected key columns will then be written to a hidden column in the accelerator-shadow table. This column, called informational unique constraint, then serves as the primary key or primary index. For more information, see the entry about the table_specifications parameter of the SYSPROC.ACCEL_ADD_TABLES stored procedure.
• If you update Db2 for z/OS tables by running the LOAD utility rather than an INSERT, UPDATE, or DELETE operation, you must set the following parameters (for the LOAD utility):
  • SHRLEVEL CHANGE
  • LOG YES
  Otherwise, the changes that were made by the LOAD utility are not detected by the incremental update function, and will thus not be reflected in your accelerator-shadow tables.
• The Db2 source tables of your accelerator-shadow tables have an attribute named DATA CAPTURE. The attribute can carry the value Y or N (default), for yes or no. When incremental updates are enabled for a table, the DATA CAPTURE attribute of the table is set to the value Y. Once set, this attribute value persists, even if the table is disabled at a later time. Bear this in mind, especially if you run applications that use the DATA CAPTURE attribute.

  The DATA CAPTURE attribute is set by an ALTER TABLE statement, which is run as part of the SYSPROC.ACCEL_SET_TABLES_REPLICATION stored procedure. However, the attribute can only be set successfully if the ID of the user who runs the stored procedure has ALTER TABLE authorization. If this is not the case, a database administrator must set the attribute for all tables in Db2 for z/OS.

• You might have to reload or even remove tables from an accelerator after the execution of an ALTER TABLE or ALTER TABLESPACE statement in Db2 for z/OS. For more information, see What to do after changing a table or table space in Db2 for z/OS

Intervention-free handling of faulty tables

A table in error is suspended from the replication process. This means updates are no longer applied and therefore the table data might be outdated.

To prevent queries from running against suspended tables, query acceleration must be disabled for these tables. This is done automatically, and each such event is reported as a warning in the event viewer for incremental updates. An intervention on your part is not required.

All that is required as a preparation is that a few extra privileges are granted. If IBM Integrated Synchronization is already installed, have a look at the steps 4 and 6 in the section Assigning user IDs. These steps describe how to grant the required privileges.

Restrictions

• It is not possible to enable tables if the table name or the schema name contains GB18030 characters (Simplified Chinese) of Unicode plane 2 (U+20000-U+2FFFF: Supplementary Ideographic Plane). Trying to do so results in an error.
• To be able to load or reload replication-enabled tables, replication must be started. Loading or reloading replication-enabled tables does not work if replication is stopped. In the unlikely situation that a replication-enabled table prevents a replication start, proceed as follows:
  1. Disable replication for this table.
  2. Remove the table from the accelerator.
  3. Restart replication.
  4. Redefine (re-add) the table to the accelerator.
  5. Re-enable replication for this table.
  6. Load the table.
• You cannot enable incremental updates for accelerator-archive tables to replicate the data of non-archived partitions.
• Even though IBM Db2 Analytics Accelerator generally supports tables that include edit procedures (EDITPROCs) for certain columns, IBM Integrated Synchronization cannot replicate such tables correctly. If you do use IBM Integrated Synchronization to replicate tables with edit procedures, you will find that the content of source and target tables differs. This restriction does not exist for replication with IBM InfoSphere Change Data Capture for z/OS (CDC).

  For more information about edit procedures, see Edit procedures.

Next steps