Solr参数mm详解

一般的mm参数设置，比较容易理解（从右到左读，更加好理解），但复杂点的则需要花点时间：

3<90%
A positive integer, followed by the less-than symbol, followed by any of the previously mentioned specifiers is a conditional specification. It indicates that if the number of optional clauses is equal to (or less than) the integer, they are all required, but if it's greater then the integer, the specification applies. In this example: if there are 1 to 3 clauses they are all required, but for 4 or more clauses only 90% are required.
2<-25% 9<-3
Multiple conditional specifications can be seperated by spaces, each one only being valid for numbers greater than the one before it. In this example: if there are 1 or 2 clauses both are required, if there are 3-9 clauses all but 25% are requred, and if there are more then 9 clauses, all but three are required.

官方解析：http://lucene.apache.org/solr/api/org/apache/solr/util/doc-files/min-should-match.html