If you are using the Lucene query parser, queries that don't specify a field name will use the defaultSearchField. The DisMax and Extended DisMax query parsers do not use this value. 

Use of the defaultSearchField element is deprecated in Solr versions 3.6 and higher. Instead, you should use the df request parameter. At some point, the defaultSearchField element may be removed。

即使用solrConfig中的df属性代替schema中的defaultSearchField。

2、关于qf

从solr的example中得到的solrConfig.xml中，qf的定义如下：

       <str name="qf">text^0.5 features^1.0 name^1.2 sku^1.5 id^10.0 manu^1.1 cat^1.4title^10.0 description^5.0 keywords^5.0 author^2.0 resourcename^1.0</str>

由于content不占任何的权重，因此如果某个文档只在content中包含关键字的话，搜索结果并不会返回这个文档。因此，对于nutch提取的索引来说，要增加content的权重，以及url的权重（如果需要的话）：

       <str name="qf">content^1.0 text^0.5 features^1.0 name^1.2 sku^1.5 id^10.0 manu^1.1 cat^1.4title^10.0 description^5.0 keywords^5.0 author^2.0 resourcename^1.0</str>

二、Search Handler

1、SearchHandler是reqestHandler中的一种，它以requestHandler作为顶层元素。

2、二级元素包括first-components,  last-components, defautls等。

3、Velocity的配置

wt：指定返回搜索结果的格式

• v.template: template name to use, without the .vm suffix. If not specified, "default"[.vm] will be used.

• v.template.<name>: overrides a file system template

• debugQuery: if true, default view displays explanations for each hit and additional debugging information in the footer.

• v.json: Escapes and wraps Velocity generated response with v.json parameter as a JavaScript function.

• v.layout: Template name that wraps main template (v.template). Main template renders to a $content that can be used in layout template.

• v.base_dir: overwrites default template load path (conf/velocity/).

• v.properties: specifies a Velocity properties file to be applied, found using the Solr resource loader mechanism. If not specified, no .properties file is loaded. Example: v.properties=velocity.properties where velocity.properties can be found using Solr's resource loader mechanism, for example in the conf/ directory (not conf/velocity which is for templates only). The .properties file could also be located inside a JAR in the lib/ directory, or other locations.

• v.contentType: sets the value of the HTTP response's Content-Type header (in case (x)html pages should be UTF-8 (instead of ISO-8859-1) encoded, make sure you set this option to text/xml;charset=UTF-8 (for XHTML) and text/html;charset=UTF-8 (for HTML), respectively)

velocity的其余配置参考：http://blog.csdn.net/jediael_lu/article/details/38039267。

4、搜索域qf

定义了从哪些域进行搜索，以及各个域之间的权重。

5、QueryParser的选择 defType，常用efType=lucene, defType=edismax

6、默认搜索域：df

若无指定搜索域，则此域作为默认的搜索域。

df/qf/defaultSearchField比较：

（1）使用solrConfig中的df属性代替schema中的defaultSearchField。

（2）df is the default field and will only take effect if the qf is not defined.

7、默认的query

q.alt: 当q字段为空时，用于设置缺省的query，通常设置q.alt为*:*。

8、 mm:minimal should match。Solr支持三种查询clause，即“必须出现”， “不能出现”和“可以出现”，分别对应于AND, -, OR。

When dealing with queries there are 3 types of "clauses" that Lucene knows about: mandatory, prohibited, and 'optional' (aka: "SHOULD") By default all words or phrases specified in the "q" param are treated as "optional" clauses unless they are preceeded by a "+" or a "-". When dealing with these "optional" clauses, the "mm" option makes it possible to say that a certain minimum number of those clauses must match (mm). Specifying this minimum number can be done in complex ways, equating to ideas like...

• At least 2 of the optional clauses must match, regardless of how many clauses there are: "2"

• At least 75% of the optional clauses must match, rounded down: "75%"

• If there are less than 3 optional clauses, they all must match; if there are 3 or more, then 75% must match, rounded up: "2<-25%"

• If there are less than 3 optional clauses, they all must match; for 3 to 5 clauses, one less than the number of clauses must match, for 6 or more clauses, 80% must match, rounded down: "2<-1 5<80%"

Full details on the variety of complex expressions supported are explained in detail here.

In Solr 1.4 and prior, you should basically set mm=0 if you want the equivilent of q.op=OR, and mm=100% if you want the equivilent of q.op=AND. In 3.x and trunk the default value of mm is dictated by the q.op param (q.op=AND => mm=100%; q.op=OR => mm=0%). Keep in mind the default operator is effected by your schema.xml <solrQueryParser defaultOperator="xxx"/> entry. In older versions of Solr the default value is 100% (all clauses must match)

9、每页返回的行数

10、返回Field的集合

fl: 是逗号分隔的列表，用来指定文档结果中应返回的 Field 集。默认为 “*”，指所有的字段。以上即返回所有域，而加上score。

11、对返回结果排序

（1）排序的字段必须是index=true

（2）<str name="sort">tstamp asc</str>

若此元素放在<default>中，则指定默认元素，query时可以改变。

若放在<invariant>中，则在query中也不可以改变。

这应该对其它元素同样适用。

参考：http://stackoverflow.com/questions/24966924/how-to-change-the-default-rank-field-from-score-to-other-filed-in-solr/24971353#24971353