Parameter	Behavior	Default value
group	If true, query results will be grouped.	false
group.field	Specifies the field by which the result will be grouped.
group.func	Specifies a function name by which the result will be grouped.
group.query	Specifies a result grouping query that will return a single group of documents.
rows	Specifies the number of groups to return.	10
start	Specifies starting point from the list of groups.
group.limit	Specifies the number of results to be returned for every group.	1
group.offset	Specifies starting point from the list of documents of every group.
sort	Specifies the field based on groups will be sorted.	score desc
group.sort	Specifies the field based on documents will be sorted within each group. The default behaviour is that if group.sort is not specified, the sort parameter value will be used.
group.format	Specifies the response format after grouping. Possible values for this parameter are simple and grouped.	Advanced grouping format
group.main	A boolean variable that tells Solr to use first the field grouping command as the main result in the response using group.format=simple. A true value will do the same.	false
group.ngroups	A boolean variable that tells Solr to include the number of groups that have matched to the query in result. A true value will do the same.	false
group.truncate	A boolean variable that tells Solr to calculate facet counts based on the most relevant document of each group matching the query. A true value will do the same.	false
group.facet	To enable/disable grouped faceting.	false
group.cache.percent	Enables caching for result grouping by configuring a value greater than zero. The maximum value is 100.	0