In this blog
we’re going to discuss the Advanced Network Compression feature, one of the
many lesser known features included with the Advanced Compression option.
keeps compressed data compressed in memory and only uncompresses the data that
gets returned to the user. Now, even that final step can be compressed as well.
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 it.
Some of the
benefits of using Advanced Network Compression are:
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.
Utilization: Compression saves bandwidth by reducing the amount of data to be
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 you to set the compression level. Two levels of compression
LOW and HIGH can be specified. LOW level uses less CPU but provides lower
compression ratio, whereas HIGH level uses more CPU and provides higher
A discussion of
the parameters that need to be configured can be found in the Advanced Network
Compression white paper (here)
or see the Oracle Database Documentation.
It should be
noted 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
If you’re using
Advanced Compression don’t forget about the added compression capability you
have with this feature. But for now the database storage optimization adventure
continues in my next blog, in which we will discuss my Advanced Compression
sessions at Oracle Open World this year – I hope to see you there!