知识点
相关文章
更多最近更新
更多Solr DisjunctionMax 注解
2019-03-27 00:23|来源: 网路
Disjunction
Max析取最大（并集）
本质多域联合搜索，并且不同域指定不同的权重，命中时取最大得分域结果作为结果得分。与直接多域boost求和是完全不同的结果。使用起来非常复杂，需要debugquery
看结果，反复尝试！
http://wiki.apache.org/solr/DisMax
http://searchhub.org/dev/2010/05/23/whats-a-dismax/
What’sa“DisMax”?Posted
byhossman
Theterm“dismax”gets
tossedaround(被抛出来)on
theSolrlistsfrequently,whichcanbefairlyconfusingtonew
users.Itoriginatedasashorthandnameforthe
DisMaxRequestHandler(whichInamedafterthe
DisjunctionMaxQueryParser,whichInamedafterthe
DisjunctionMaxQueryclassthatitusesheavily).Inrecent
years,theDisMaxRequestHandlerandtheStandardRequestHandlerwere
bothrefactoredinto(重构)
asingleSearchHandlerclass,and
nowtheterm“dismax”usuallyreferstothe
DisMaxQParser.
注解:dismax现在对应于DisMaxQParser，而DismaxRequestHandler与standardRequestHandler重构到SearchHandler中
ClearasMudd,
right?
Regardlessofwhetheryou
usetheDisMaxRequestHandlerviatheqt=dismax
parameter,orusetheSearchHandlerwiththeDisMaxQParserviadefType=dismaxtheendresultisthatyourqparametergetsparsedbythe
DisjunctionMaxQueryParser.
注解：qt=dismax,采取DisMaxRequestHandler,而defType=dismax,是SearchHandler中使用DisMaxQParser，二者q的参数采取DisJunctionMaxQueryParser解析
The
originalgoalsofdismax(whichevermeaningyoumightinfer)
haveneverchanged:
…supportsasimplified
versionoftheLuceneQueryParsersyntax.Quotescanbeusedto
groupphrases(分组短语),and
+/-canbeusedtodenotemandatory(强制性、必选的)andoptional(可选的)clauses…butallotherLucenequeryparser
specialcharactersareescapedtosimplifytheuserexperience.The
handlertakesresponsibilityforbuildingagoodqueryfromthe
user’sinputusingBooleanQueriescontainingDisjunctionMaxQueries
acrossfieldsandboostsyouspecifyItalsoallowsyoutoprovide
additionalboostingqueries,boostingfunctions,andfiltering
queriestoartificially(人工)affecttheoutcomeofallsearches.Theseoptionscanall
bespecifiedasdefaultparametersforthehandlerinyour
solrconfig.xmloroverriddentheSolrqueryURL.
Inshort:Youworryabout
whatfieldsandboostsyouwanttousewhenyouconfigureit,your
usersjustgiveyouwordsw/oworryingtoomuchabout
syntax.
注解:dismax句柄主要负责使用布尔查询封装DisjunctionMaxQueries，同时允许手工执行query激励、函数激励、过滤query影响最终搜索结果。所有参数可以通过在solrconfig.xml中配置，作为全局查询用，也可以通过url添加参数，在每一次或者每一类查询中动态使用。
Themagicofdismax(inmy
opinion)comesfromthequerystructureitproduces.Whatit
essentiallyboilsdowntois
matrixmultiplication:aonecolumnmatrixofeach“chunk”of
youruser’sinput,multipliedbyaonerowmatrixoftheqffieldstoproduceabigmatrixofeveryfield:chunk
permutation(排列).
ThematrixisthenturnedintoaBooleanQueryconsistingof
DisjunctionMaxQueriesforeachrow
inthematrix.DisjunctionMaxQueryisusedbecause
it’sscoreisdeterminedbythemaximumscoreofit’s
subclauses―insteadofthesumlikeaBooleanQuery―sonoone
wordfromtheuserinputdominatesthefinalscore.Thebestwayto
explainthisiswithanexample,solet’sconsiderthefollowing
input…
span lang="EN-US">defType = dismax</span> <span lang="EN-US"><span> </span>mm = 50%</span> <span lang="EN-US"><span> </span>qf = features^2 name^3</span> <span lang="EN-US"><span> </span>q = +"apache solr" search server</span>
Firstoff,weconsiderthe
“markup”charactersoftheparserthatappearinthisqstring:
whitespace�dividinginput
stringintochunk(
分词)quotes�makesasinglephrase
chunk(
括号)+�makesachunkmandatory
(
组合关系)
Sowehave3“chunks”ofuserinput:
“apachesolr”(must
match)“search”(should
match)“server”(should
match>
Ifwe“multiply”thatwith
ourqflist(features,name)wegeta
matrixlikethis…
features:”apache |
name:”apache |
(mustmatch) |
features:”search” |
name:”search” |
(shouldmatch) |
features:”server” |
name:”server” |
(shouldmatch) |
Ifwethenfactorinthemmparamtodetermingthe“minimumnumberof
‘ShouldMatch’clausesthat(ahem)mustmatch”(50%of2==1)we
getthefollowingquerystructure(inpsuedo-code)…
<span lang="EN-US">q = BooleanQuery(</span>
<span lang="EN-US"><span> </span><b>minNumberShouldMatch</b> => 1,</span>
<span lang="EN-US"><span> </span>booleanClauses => ClauseList(</span>
<span lang="EN-US"><span> </span>MustMatch(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>PhraseQuery("features","apache solr")^2,</span>
<span lang="EN-US"><span> </span>PhraseQuery("name","apache solr")^3)</span>
<span lang="EN-US"><span> </span>),</span>
<span lang="EN-US"><span> </span>ShouldMatch(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>TermQuery("features","search")^2,</span>
<span lang="EN-US"><span> </span>TermQuery("name","search")^3)</span>
<span lang="EN-US"><span> </span>),</span>
<span lang="EN-US"><span> </span>ShouldMatch(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>TermQuery("features","server")^2,</span>
<span lang="EN-US"><span> </span>TermQuery("name","server")^3))</span>
<span lang="EN-US">));</span>
<span lang="EN-US"> </span>
<span style="font-size:9.0pt"><b>注解：<span lang="EN-US">boolean</span>查询这个是最最基本的原子查询，其他高级查询都是基于这个查询的组合、封装，<span lang="EN-US">Dismax</span>也是如此。从<span lang="EN-US">dismax qp</span>分解过程和定义看，<span lang="EN-US">dismax</span>也是分解为<span lang="EN-US">boolean</span>查询，并且<span lang="EN-US">field</span>激励也同一般域<span lang="EN-US">boost</span>一致，但是不同的时候<span lang="EN-US">dismax</span>是以最大得分作为最终得分，而一般多域独立<span lang="EN-US">boost</span>时候是求和得分。<br>
<br></b></span>
Withmesofar
right?
Wherepeopletendtoget
trippedup(绊倒),isinthinkingabouthowSolr’sper-fieldanalysis
configuration(inschema.xml)impactsallofthis.Ourexample
abovewasprettystraightforward,butletsconsiderforamoment
whatmighthappenif:
The
name
fieldusestheWordDelimiterFilter（单词分割符过滤器）atquerytimebutfeaturesdoesnot.The
featuresfieldisconfiguredsothat“the”isastopword,butnameis
not.
Nowlet’slookatwhatwe
getwhenourinputparametersarestructurallysimilartowhatwe
hadbefore,butjustdifferentenoughtoforWordDelimiterFilter
andStopFiltertocomeintoplay…
<span lang="EN-US">defType = dismax</span> <span lang="EN-US"><span> </span>mm = 50%</span> <span lang="EN-US"><span> </span>qf = features^2 name^3</span> <span lang="EN-US"><span> </span>q = +"apache solr" the search-server</span>
Ourresultingqueryisgoing
tobesomethinglike…
<span lang="EN-US">q = BooleanQuery(</span>
<span lang="EN-US"><span> </span>minNumberShouldMatch => 1,</span>
<span lang="EN-US"><span> </span>booleanClauses => ClauseList(</span>
<span lang="EN-US"><span> </span><span style="color:red">MustMatch</span>(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>PhraseQuery("features","apache solr")^2,</span>
<span lang="EN-US"><span> </span>PhraseQuery("name","apache solr")^3)</span>
<span lang="EN-US"><span> </span>),</span>
<span lang="EN-US"><span> </span><span style="color:red">ShouldMatch</span>(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>TermQuery("name","the")^3)</span>
<span lang="EN-US"><span> </span>),</span>
<span lang="EN-US"><span> </span><span style="color:red">ShouldMatch</span>(DisjunctionMaxQuery(</span>
<span lang="EN-US"><span> </span>TermQuery("features","search-server")^2,</span>
<span lang="EN-US"><span> </span>PhraseQuery("name","search server")^3))</span>
<span lang="EN-US"><span> </span>));</span>
Theuseof
WordDelimiterFilterhasn’tchangedthingsverymuch:featuresis
treating“search-server”asasingleTerm,whileinthenamefieldwearesearchingforthephrase“search
server”―hopefullythisshouldn’tsurpriseanyonegiventheuseof
WordDelimiterFilterforthenamefield(presumablythat’swhyit’s
beingused).ThisDisjunctionMaxQuerystill“makessense”,but
otherfieldswithoddanalysisthatproduceless/moreTokensthena
“typical”fieldforthesamethunkmightproducequeriesthat
aren’taseasilytounderstand.Inparticularconsiderwhathas
happenedinourexamplewiththeword“the”:Because“the”isa
stopwordinthefeaturesfield,noQueryobjectis
producedforthatfield/chunkcombination.ButaQueryisproduced
forthenamefield,whichmeansthetotalnumberof
“ShouldMatch”clausesinourtoplevelqueryisstill2soour
minNumberShouldMatchisstill1(50%of2==1).
Thistypeofsituationtends
toconfusealotofpeople:since“the”isastopwordinone
field,theydon’texpectittomatterinthefinalquery―butas
longasatleastoneqffieldproducesaTokenforit
(nameinourexample)itwillbeincludedinthefinal
query,andwillcontributetothecountof“ShouldMatch”
clauses.
So,what’sthetakeaway
fromallofthis?
DisMaxisacomplicated
creature.Whenusingit,youneedtoconsiderallofit’s
optionscarefully,andlookatthedebugQuery=true
outputwhileexperimentingwithdifferentquerystringsand
differentanalysisconfigurationstomakereallysureyou
understandhowqueriesfromyouruserswillbeparsed.
注解：dismax构造非常复杂，使用的时候需要仔细考虑所有选项，同时，开启debugQuery=true，针对不同的查询串和分词器。
Forqf(QueryFields),pf(PhraseFields),
mm(Minimum‘Should’Match),andtie(TieBreaker),
see:theSolr
WikiDisMaxQParserPlugin.
Solr:
ForcingitemswithallquerytermstothetopofaSolrsearch
RobotLibrarian
LucidImaginationSolrPoweredISFDB�Part
#10:TweakingRelevancy
http://searchhub.org/dev/2011/06/20/solr-powered-isfdb-part-10/
LucidImaginationSolrPoweredISFDB�Part
#11:UsingDisMax
http://searchhub.org/dev/2011/08/08/solr-powered-isfdb-part-11/
http://tm.durusau.net/?p=21573
Using
Solr’sDismaxTieParameterAnotherWordForIt(tie
breake配合断路器)
http://java.dzone.com/articles/using-solrs-dismax-tie
SolrPoweredISFDB�Part#11:Using
DisMax
http://searchhub.org/dev/2011/06/20/solr-powered-isfdb-part-10/
转自：http://aliapp.blog.51cto.com/8192229/1325845
相关问答
更多-
java 自定义的注解有什么作用[2023-12-13]
自定义注解，可以应用到反射中，比如自己写个小框架。 如实现实体类某些属性不自动赋值，或者验证某个对象属性完整性等 本人自己用过的验证属性值完整性： @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface IgnoreProperty { } 然后实体类中： public class TarResearch implements Serializable{ @IgnoreProperty private ... -
Spring注解和SpringMVC注解是同一种注解吗,如果不是请举例![2021-12-07]
Spring 整个开源架构就包括SpringMVC Spring SpringJDBC 他们是完美结合一起的，因为本来就是一个整体的开源框架。 至于说的注解肯定是同一种机制，但不一定是同一种注解，毕竟注解的名称都不一样@Controller,正因为他们之间的完美结合，所以市场上大多用SpringMVC取代了Struts(不过最近好像Angular.js发展势头迅猛，可以替代上述俩种)， -
spring mvc 注解 @requestMapping[2022-09-13]
靠spring内部的相应处理类了，先在xml配置好。 映射处理器有BeanNameUrlHandlerMapping和SimpleUrlhandlerMapping一加入springmvc注解扫描junit就报错[2023-07-30]
main调用的时候不能通过 @Autowired 来进行注解，因为你没有启动项目，相当于你注入的东西没有没有被使用，使用main方法使用的话，必须使用getbeanspring如何使用注解定义映射信息[2023-03-19]
先开启扫描 在要注入的类前加 @Controller public class xxxx{ }java中spring框架用了哪些注解？[2023-06-05]
很多 IOC的很多来自包扫描spring mvc 注解 @requestMapping[2022-07-30]
靠spring内部的相应处理类了，先在xml配置好。 映射处理器有BeanNameUrlHandlerMapping和SimpleUrlhandlerMapping 开启自动扫描action路径。 再以下两个class激活@requestMapping接口。 @Controller 控制器 组合使用 怎么使用才是重点，原理的话研究下spring的相关类的源代码。