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Database CDC Integration using Striim Hot Cache

Hazelcast IMDG Enterprise

Change Data Capture (CDC) refers to the technology for identifying and capturing changes made to a data source. These changes can then be applied to another data repository or made available in a format supported by data integration tools.

Striim is a real-time data integration and streaming analytics software platform. It uses CDC (Change Data Capture) mechanism to detect changes performed on a data source.

Hazelcast Striim Hot Cache, the integration solution of Hazelcast and Striim, enables real-time, push-based propagation of changes from the database to the cache. The following sections describe this integration.

Introduction

Through CDC, Striim is able to recognize which tables and key values have changed. It immediately captures these changes with their table and key, and pushes the changes into a cache. Supported databases are Oracle, My SQL and Microsoft SQL Server.

When it comes to Hazelcast, you can get the changes in a database and put them into your Hazelcast IMDG member using a "writer" developed by Striim, i.e., Hazelcast Writer. This writer creates a Hazelcast client once you start Striim, to connect to your IMDG member.

Supported Versions

This integration only works with Hazelcast IMDG 3.x versions. Support for 4.x will be added in the near future.

Logging

You can enable logging to see the status of the Hazelcast client created by the Hazelcast Writer. For this, you need to add the following line to the server.sh file on the machine where Striim is running:

-Dhazelcast.logging.type=log4j

The server.sh file is typically located at the /opt/striim/bin directory.

You can also set the logging level by adding the following line to the log4j.server.properties file:

log4j.logger.com.hazelcast=debug

The log4j.server.properties file is typically located at the /opt/striim/conf directory.

In the above example line, the logging level is set as DEBUG. The following lists all the available levels:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

The logs are written into the striim.server.log which is typically located at the /opt/striim/logs directory.

The above settings are for the Hazelcast Client created by the writer. You can also change the logging level dynamically for Hazelcast Writer. Follow the below instructions for this:

  1. Open the Striim console using the console.sh command. See here for the usage of this command.

  2. While in the console, run the following command:

    set loglevel = {com.webaction.proc.HazelcastWriter_1_0:debug};

Fully Working Example Application

We have created a full example application with step-by-step instructions which guides you through using Striim to load data from an Oracle database using the Striim Hazelcast Writer. We recommend you start here before applying this to your own application.

Further Resources

You can refer to here for more information on Hazelcast Writer.

Download a fully loaded evaluation copy of Striim for Hazelcast Hot Cache.