What does this line in a WSDL file mean?

Question

In a Magento forum someone wrote that removing this line from the WSDL file has a huge impact on the performance of the SOAP server:

<import namespace="http://schemas.xmlsoap.org/soap/encoding/"   
     schemaLocation="http://schemas.xmlsoap.org/soap/encoding/" />

• What does this line actually do?
• Can it really be removed? (Everything seems to work fine, but who knows...)
• Is it possible this line causes performance issues?
• EDIT: Has this something to do with XML namespaces?

Answer 1

It links the namespace URI (namespace="http://schemas.xmlsoap.org/soap/encoding/) with the location URL (schemaLocation="http://schemas.xmlsoap.org/soap/encoding/)

I cannot see any point in having this if it creates a serious performance hit. And if it works, it works!

As it links to a URL it is safe to assume that some performance can be gained by removing it. It depends on the implementation of course how much.