We’ll focus in this blog post on Search Handlers : a class of request handler that processes search requests.
N.B. it’s out of scope for this blog post, but a request handler can be a complex component that contains advanced logic and append/default various request parameters to the user search request, transparently [1]
The qt parameter is a request parameter supported by the Apache Solr Request Dispatcher.
Its original scope was to pass the request handler to use through a request parameter.
This parameter is strictly tied to the handleSelect attribute of the Solr Request Dispatcher:
The first configurable item is the handleSelect
attribute on the <requestDispatcher>
element itself. This attribute can be set to one of two values, either “true” or “false”. It governs how Solr responds to requests such as /select?qt=XXX
. The default value “false” will ignore requests to /select
if a requestHandler is not explicitly registered with the name /select
. A value of “true” will route query requests to the parser defined with the qt
value.
In recent versions of Solr, a /select
requestHandler is defined by default, so a value of “false” will work fine.
Apache Solr Wiki
We have now clarified the definitions and the scope of the blog post, let’s see if this is always true, and what happens in SolrJ.