LogicalDecode | Demo for PostgreSQL Logical Decoding with JDBC

LogicalDecode is a Java library typically used in Telecommunications, Media, Media, Entertainment applications. LogicalDecode has no bugs, it has no vulnerabilities, it has build file available, it has a Permissive License and it has low support. You can download it from GitHub.

It's useful to understand what physical replication is in order to understand logical decoding. Physical replication extends the functionality of recovery mode. Write Ahead Logs are written to disk before the actual database. These files contain enough information to recreate the transaction in the event of a catastrophic shutdown. In the event of an emergency shutdown (power fail, OOM kill) when the server comes back online it will attempt to apply the outstanding WAL up to the point of the shutdown. This is referred to as recovery mode. Physical replication takes advantage of this infrastructure built into the server. The standby is started in recovery mode and WAL created by the primary are applied to the standby. How that occurs is beyond the scope but you can read about it here . The interesting bit here is that we have a mechanism by which to access the changes in the heap without connecting to the database. There are a few caveats though which is where Logical Decoding comes to the rescue. First; WAL's are binary and their format is not guaranteed to be stable (in other words they can change from version to version) and second they contain changes for every database in the server. Logical decoding changes all of that by. Providing changes for only one database per slot Defining an API which facilitates writing an output plugin to output the changes in any format you define.