如何用StreamFactory构建流表达式

Question

我正在尝试为solr流构建let表达式，但它给出的错误提示是: java.io.IOException:无效的流表达式col(samples，score) -函数'col‘未知(未映射到有效的TupleStream)

StreamFactory = new StreamFactory().withDefaultZkHost(zookeeper)
        .withFunctionName("search", CloudSolrStream.class) 
        .withFunctionName("select", SelectStream.class)
        .withFunctionName("merge", MergeStream.class) 
        .withFunctionName("sort", SortStream.class) 
        .withFunctionName("tuple", TupStream.class) 
        .withFunctionName("rollup", RollupStream.class) 
        .withFunctionName("hashJoin", HashJoinStream.class)
        .withFunctionName("count", CountMetric.class) 
        .withFunctionName("facet", FacetStream.class) 
        .withFunctionName("sum", SumMetric.class) 
        .withFunctionName("unique", UniqueStream.class) 
        .withFunctionName("significantTerms", SignificantTermsStream.class)
        .withFunctionName("stats", StatsStream.class)
        .withFunctionName("innerJoin", InnerJoinStream.class) 
        .withFunctionName("issnMerge", IssnMergeStream.class) 
        .withFunctionName("intersect", IntersectStream.class)
        .withFunctionName("boostByEra", BoostBooksByEraExpression.class)
        .withFunctionName("determineRRec", DetermineRepresentativeRecord.class)
        .withFunctionName("plist", ParallelListStream.class)
        .withFunctionName("let", LetStream.class);

我的表达式如下：

let(samples=search(wc_art，qt="/select"，q="al:next qt= al:generation"，fq="_delete:false"，fq="_namespace:default"，fl="score，numdocs()，id"，rows=10，fq="{!lucene q.op=OR}pa:(medline)"，defType=edismax，q.op=AND，sort="score desc")，responses=col(样本，score)，summary=describe(responses))

Answer 1

col函数是在Solr7中添加的，因此如果您的Solr安装版本比该版本旧，则该函数将不可用。升级到更新的版本。