org.apache.solr.request
Class UnInvertedField

java.lang.Object
  org.apache.solr.request.UnInvertedField

public class UnInvertedField
extends Object

Final form of the un-inverted field: Each document points to a list of term numbers that are contained in that document. Term numbers are in sorted order, and are encoded as variable-length deltas from the previous term number. Real term numbers start at 2 since 0 and 1 are reserved. A term number of 0 signals the end of the termNumber list. There is a single int[maxDoc()] which either contains a pointer into a byte[] for the termNumber lists, or directly contains the termNumber list if it fits in the 4 bytes of an integer. If the first byte in the integer is 1, the next 3 bytes are a pointer into a byte[] where the termNumber list starts. There are actually 256 byte arrays, to compensate for the fact that the pointers into the byte arrays are only 3 bytes long. The correct byte array for a document is a function of it's id. To save space and speed up faceting, any term that matches enough documents will not be un-inverted... it will be skipped while building the un-inverted field structure, and will use a set intersection method during faceting. To further save memory, the terms (the actual string values) are not all stored in memory, but a TermIndex is used to convert term numbers to term values only for the terms needed after faceting has completed. Only every 128th term value is stored, along with it's corresponding term number, and this is used as an index to find the closest term and iterate until the desired number is hit (very much like Lucene's own internal term index).

Constructor Summary

UnInvertedField(String field, SolrIndexSearcher searcher)

Method Summary

org.apache.solr.common.util.NamedList	getCounts(SolrIndexSearcher searcher, DocSet baseDocs, int offset, int limit, Integer mincount, boolean missing, String sort, String prefix)
StatsValues	getStats(SolrIndexSearcher searcher, DocSet baseDocs, String[] facet) Collect statistics about the UninvertedField.
static UnInvertedField	getUnInvertedField(String field, SolrIndexSearcher searcher)
long	memSize()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

UnInvertedField

public UnInvertedField(String field,
                       SolrIndexSearcher searcher)
                throws IOException

Throws:

IOException

Method Detail

memSize

public long memSize()

getCounts

public org.apache.solr.common.util.NamedList getCounts(SolrIndexSearcher searcher,
                                                       DocSet baseDocs,
                                                       int offset,
                                                       int limit,
                                                       Integer mincount,
                                                       boolean missing,
                                                       String sort,
                                                       String prefix)
                                                throws IOException

Throws:

IOException

getStats

public StatsValues getStats(SolrIndexSearcher searcher,
                            DocSet baseDocs,
                            String[] facet)
                     throws IOException

Collect statistics about the UninvertedField. Code is very similar to getCounts(org.apache.solr.search.SolrIndexSearcher, org.apache.solr.search.DocSet, int, int, Integer, boolean, String, String) It can be used to calculate stats on multivalued fields.

This method is mainly used by the StatsComponent.

Parameters:

searcher - The Searcher to use to gather the statistics

baseDocs - The DocSet to gather the stats on

facet - One or more fields to facet on.

Returns:

The StatsValues collected

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

getUnInvertedField

public static UnInvertedField getUnInvertedField(String field,
                                                 SolrIndexSearcher searcher)
                                          throws IOException

Throws:

IOException