org.apache.solr.search.join

Class ScoreJoinQParserPlugin

  • All Implemented Interfaces:
    SolrInfoMBean, NamedListInitializedPlugin


    public class ScoreJoinQParserPlugin
    extends QParserPlugin
    Create a query-time join query with scoring. It just calls JoinUtil.createJoinQuery(String, boolean, String, Query, org.apache.lucene.search.IndexSearcher, ScoreMode). It runs subordinate query and collects values of "from" field and scores, then it lookups these collected values in "to" field, and yields aggregated scores. Local parameters are similar to JoinQParserPlugin {!join} This plugin doesn't have own name, and is called by specifying local parameter {!join score=...}.... Note: this parser is invoked even if you specify score=none.
    Example:q={!join from=manu_id_s to=id score=total}foo
    • from - "foreign key" field name to collect values while enumerating subordinate query (denoted as foo in example above). it's better to have this field declared as type="string" docValues="true". note: if docValues are not enabled for this field, it will work anyway, but it costs some memory for UninvertingReader. Also, numeric doc values are not supported until LUCENE-5868. Thus, it only supports DocValuesType.SORTED, DocValuesType.SORTED_SET, DocValuesType.BINARY.
    • fromIndex - optional parameter, a core name where subordinate query should run (and from values are collected) rather than current core.
      Example:q={!join from=manu_id_s to=id score=total fromIndex=products}foo
    • to - "primary key" field name which is searched for values collected from subordinate query. it should be declared as indexed="true". Now it's treated as a single value field.
    • score - one of ScoreMode: none,avg,total,max,min. Capital case is also accepted.
    • Method Detail

      • getCoreName

        public static String getCoreName(String fromIndex,
                                         CoreContainer container)
        Returns an String with the name of a core.

        This method searches the core with fromIndex name in the core's container. If fromIndex isn't name of collection or alias it's returns fromIndex without changes. If fromIndex is name of alias but if the alias points to multiple collections it's throw SolrException.ErrorCode.BAD_REQUEST because multiple shards not yet supported.

        Parameters:
        fromIndex - name of the index
        container - the core container for searching the core with fromIndex name or alias
        Returns:
        the string with name of core