Book Image

IBM InfoSphere Replication Server and Data Event Publisher

By : Pav Kumar-Chatterjee, Pav Kumar Chatterjee
Book Image

IBM InfoSphere Replication Server and Data Event Publisher

By: Pav Kumar-Chatterjee, Pav Kumar Chatterjee

Overview of this book

Business planning is no longer just about defining goals, analyzing critical issues, and then creating strategies. You must aid business integration by linking changed-data events in DB2 databases on Linux, UNIX, and Windows with EAI solutions , message brokers, data transformation tools, and more. Investing in this book will save you many hours of work (and heartache) as it guides you around the many potential pitfalls to a successful conclusion. This book will accompany you throughout your Q replication journey. Compiled from many of author's successful projects, the book will bring you some of the best practices to implement your project smoothly and within time scales. The book has in-depth coverage of Event Publisher, which publishes changed-data events that can run updated data into crucial applications, assisting your business integration processes. Event Publisher also eliminates the hand coding typically required to detect DB2 data changes that are made by operational applications. We start with a brief discussion on what replication is and the Q replication release currently available in the market. We then go on to explore the world of Q replication in more depth. The latter chapters cover all the Q replication components and then talk about the different layers that need to be implemented—the DB2 database layer, the WebSphere MQ layer, and the Q replication layer. We conclude with a chapter on how to troubleshoot a problem. The Appendix (available online) demonstrates the implementation of 13 Q replication scenarios with step-by-step instructions.
Table of Contents (12 chapters)
IBM InfoSphere Replication Server and Data Event Publisher
Credits
About the Author
About the Reviewer
Preface

The IBMQREP_SIGNAL control table


The IBMQREP_SIGNAL table is a mechanism used to communicate with Q Capture. Remember that Q Capture reads from the DB2 logs, so if we insert data into the IBMQREP_SIGNAL table, then this will be picked up by Q Capture.

Note

The Q Capture does not read the IBMQREP_SIGNAL table, it detects when a row has been inserted into the table by reading the DB2 logs (it is the only control table that has DATA CAPTURE CHANGES set).

The following shows the structure of the IBMQREP_SIGNAL table:

SIGNAL_TIME TS NNWD CURRENT TS
SIGNAL_TYPE VCHAR(30) NOT NULL
SIGNAL_SUBTYPE VCHAR(30)
SIGNAL_INPUT_IN VCHAR(500)
SIGNAL_STATE CHAR(1) NNWD 'P'
SIGNAL_LSN CHAR(10) FOR BIT DATA

Let's look at each column in detail:

  • SIGNAL_TIME: Timestamp that is used to uniquely identify the row. Q Capture uses this value to find the correct row in the signal table to indicate when it completed processing the Q Capture signal.

  • SIGNAL_TYPE: This is a flag that indicates the type of signal that was posted...