Tomcat config: 'compression' versus 'SSLDisableCompression'

Question

I was wondering if someone could clarify the difference between the configuration parameters 'compression' versus 'SSLDisableCompression' or point me to some documentation that explains it?

Do they both refer to the same type of compression?

Based on the Tomcat docs I know the former controls whether or not the connector uses gzip compression. Regarding the latter, the Tomcat docs say:
"Disables compression if set to true and OpenSSL supports disabling compression.". Is that referring to a different type of compression?

Here is the behavior I'm seeing:

--compression=on and SSLDisableCompression=false, the responses are gzip'd
--compression=on and SSLDisableCompression=true, the responses are gzip'd
--compression=off and SSLDisableCompression=false, the responses are not gzip'd

Environment:

Tomcat 7.0.40
Java 7
RHEL (Linux)
APR/native connector with SSL
OpenSSL 1.0.0
APR 1.4.8

Answer 1

 Do they both refer to the same type of compression?

No.

Regarding the latter, the Tomcat docs say:  "Disables compression if set to true and OpenSSL supports disabling compression.". Is that referring to a different type of compression?

Yes.

The Tomcat connector implements compression. The SSL/TLS protocol has a separate compression implementation.

I'd guess (no testing to back this up) that you'd be better off with using the connector compression as you can tailor that to the correct mime-types.

I'd also guess that if you have one, enabling the other doesn't buy you much.