Advanced Compression includes a number of lesser-known features. To ensure that users are aware of all the features of Advanced Compression we are going to review all of these lesser-known features in my upcoming blogs. Today we are going to revisit Advanced Network Compression, a feature included with Advanced Compression.

Oracle Database, with Advanced Row and Index Compression, keeps compressed data compressed in memory and only uncompresses the columns that are returned to the user. Now, even that final step can be compressed as well. 

Advanced Network Compression reduces the size of Oracle Net Session Data Unit (SDU) transmitted over a data connection, thereby reducing the time required to transmit the SDU. The server compresses before sending on the network, data travels over the network in compressed form, and the client reads and uncompresses.

Some of the benefits of using Advanced Network Compression are:

  • Increased Effective Network Throughput: Compression allows transmission of large datasets in less time. SQL query response becomes faster due to the reduced transmission time, especially in constrained bandwidth environments.
  • Reduced Bandwidth Utilization: Compression saves bandwidth by reducing the amount of data transmitted, allowing other applications to use it. This also helps in reducing the cost of providing network bandwidth.

To use Advanced Network Compression a number of parameters need to be configured in the sqlnet.ora file, which resides both on the client and database server. 

One of these parameters enables users to set the compression level — LOW or HIGH. LOW level uses less CPU but provides lower compression ratio, whereas HIGH level uses more CPU and provides higher compression ratio. 

A discussion of the parameters can be found in the Advanced Network Compression white paper (here) or see the Oracle Database Documentation (here).

Please note that enabling compression may not always increase performance, and can be affected by several factors. The Advanced Network Compression white paper provides guidelines on when Advanced Network Compression can increase performance.