org.apache.lucene.search
Class NumericRangeQuery<T extends Number>

java.lang.Object
  extended by org.apache.lucene.search.Query
      extended by org.apache.lucene.search.MultiTermQuery
          extended by org.apache.lucene.search.NumericRangeQuery<T>
All Implemented Interfaces:
Cloneable

public final class NumericRangeQuery<T extends Number>
extends MultiTermQuery

A Query that matches numeric values within a specified range. To use this, you must first index the numeric values using IntField, FloatField, LongField or DoubleField (expert: NumericTokenStream). If your terms are instead textual, you should use TermRangeQuery. NumericRangeFilter is the filter equivalent of this query.

You create a new NumericRangeQuery with the static factory methods, eg:

 Query q = NumericRangeQuery.newFloatRange("weight", 0.03f, 0.10f, true, true);
 
matches all documents whose float valued "weight" field ranges from 0.03 to 0.10, inclusive.

The performance of NumericRangeQuery is much better than the corresponding TermRangeQuery because the number of terms that must be searched is usually far fewer, thanks to trie indexing, described below.

You can optionally specify a precisionStep when creating this query. This is necessary if you've changed this configuration from its default (4) during indexing. Lower values consume more disk space but speed up searching. Suitable values are between 1 and 8. A good starting point to test is 4, which is the default value for all Numeric* classes. See below for details.

This query defaults to MultiTermQuery.CONSTANT_SCORE_AUTO_REWRITE_DEFAULT. With precision steps of ≤4, this query can be run with one of the BooleanQuery rewrite methods without changing BooleanQuery's default max clause count.

How it works

See the publication about panFMP, where this algorithm was described (referred to as TrieRangeQuery):

Schindler, U, Diepenbroek, M, 2008. Generic XML-based Framework for Metadata Portals. Computers & Geosciences 34 (12), 1947-1955. doi:10.1016/j.cageo.2008.02.023

A quote from this paper: Because Apache Lucene is a full-text search engine and not a conventional database, it cannot handle numerical ranges (e.g., field value is inside user defined bounds, even dates are numerical values). We have developed an extension to Apache Lucene that stores the numerical values in a special string-encoded format with variable precision (all numerical values like doubles, longs, floats, and ints are converted to lexicographic sortable string representations and stored with different precisions (for a more detailed description of how the values are stored, see NumericUtils). A range is then divided recursively into multiple intervals for searching: The center of the range is searched only with the lowest possible precision in the trie, while the boundaries are matched more exactly. This reduces the number of terms dramatically.

For the variant that stores long values in 8 different precisions (each reduced by 8 bits) that uses a lowest precision of 1 byte, the index contains only a maximum of 256 distinct values in the lowest precision. Overall, a range could consist of a theoretical maximum of 7*255*2 + 255 = 3825 distinct terms (when there is a term for every distinct value of an 8-byte-number in the index and the range covers almost all of them; a maximum of 255 distinct values is used because it would always be possible to reduce the full 256 values to one term with degraded precision). In practice, we have seen up to 300 terms in most cases (index with 500,000 metadata records and a uniform value distribution).

Precision Step

You can choose any precisionStep when encoding values. Lower step values mean more precisions and so more terms in index (and index gets larger). The number of indexed terms per value is (those are generated by NumericTokenStream):

  indexedTermsPerValue = ceil(bitsPerValue / precisionStep)

As the lower precision terms are shared by many values, the additional terms only slightly grow the term dictionary (approx. 7% for precisionStep=4), but have a larger impact on the postings (the postings file will have more entries, as every document is linked to indexedTermsPerValue terms instead of one). The formula to estimate the growth of the term dictionary in comparison to one term per value:

  \mathrm{termDictOverhead} = \sum\limits_{i=0}^{\mathrm{indexedTermsPerValue}-1} \frac{1}{2^{\mathrm{precisionStep}\cdot i}}

On the other hand, if the precisionStep is smaller, the maximum number of terms to match reduces, which optimizes query speed. The formula to calculate the maximum number of terms that will be visited while executing the query is:

  \mathrm{maxQueryTerms} = \left[ \left( \mathrm{indexedTermsPerValue} - 1 \right) \cdot \left(2^\mathrm{precisionStep} - 1 \right) \cdot 2 \right] + \left( 2^\mathrm{precisionStep} - 1 \right)

For longs stored using a precision step of 4, maxQueryTerms = 15*15*2 + 15 = 465, and for a precision step of 2, maxQueryTerms = 31*3*2 + 3 = 189. But the faster search speed is reduced by more seeking in the term enum of the index. Because of this, the ideal precisionStep value can only be found out by testing. Important: You can index with a lower precision step value and test search speed using a multiple of the original step value.

Good values for precisionStep are depending on usage and data type:

Comparisons of the different types of RangeQueries on an index with about 500,000 docs showed that TermRangeQuery in boolean rewrite mode (with raised BooleanQuery clause count) took about 30-40 secs to complete, TermRangeQuery in constant score filter rewrite mode took 5 secs and executing this class took <100ms to complete (on an Opteron64 machine, Java 1.5, 8 bit precision step). This query type was developed for a geographic portal, where the performance for e.g. bounding boxes or exact date/time stamps is important.

Since:
2.9

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.search.MultiTermQuery
MultiTermQuery.ConstantScoreAutoRewrite, MultiTermQuery.RewriteMethod, MultiTermQuery.TopTermsBoostOnlyBooleanQueryRewrite, MultiTermQuery.TopTermsScoringBooleanQueryRewrite
 
Field Summary
 
Fields inherited from class org.apache.lucene.search.MultiTermQuery
CONSTANT_SCORE_AUTO_REWRITE_DEFAULT, CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE, CONSTANT_SCORE_FILTER_REWRITE, field, rewriteMethod, SCORING_BOOLEAN_QUERY_REWRITE
 
Method Summary
 boolean equals(Object o)
           
 T getMax()
          Returns the upper value of this range query
 T getMin()
          Returns the lower value of this range query
 int getPrecisionStep()
          Returns the precision step.
protected  TermsEnum getTermsEnum(Terms terms, AttributeSource atts)
          Construct the enumeration to be used, expanding the pattern term.
 int hashCode()
           
 boolean includesMax()
          Returns true if the upper endpoint is inclusive
 boolean includesMin()
          Returns true if the lower endpoint is inclusive
static NumericRangeQuery<Double> newDoubleRange(String field, Double min, Double max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a double range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4).
static NumericRangeQuery<Double> newDoubleRange(String field, int precisionStep, Double min, Double max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a double range using the given precisionStep.
static NumericRangeQuery<Float> newFloatRange(String field, Float min, Float max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a float range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4).
static NumericRangeQuery<Float> newFloatRange(String field, int precisionStep, Float min, Float max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a float range using the given precisionStep.
static NumericRangeQuery<Integer> newIntRange(String field, Integer min, Integer max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a int range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4).
static NumericRangeQuery<Integer> newIntRange(String field, int precisionStep, Integer min, Integer max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a int range using the given precisionStep.
static NumericRangeQuery<Long> newLongRange(String field, int precisionStep, Long min, Long max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a long range using the given precisionStep.
static NumericRangeQuery<Long> newLongRange(String field, Long min, Long max, boolean minInclusive, boolean maxInclusive)
          Factory that creates a NumericRangeQuery, that queries a long range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4).
 String toString(String field)
          Prints a query to a string, with field assumed to be the default field and omitted.
 
Methods inherited from class org.apache.lucene.search.MultiTermQuery
getField, getRewriteMethod, getTermsEnum, rewrite, setRewriteMethod
 
Methods inherited from class org.apache.lucene.search.Query
clone, createWeight, extractTerms, getBoost, setBoost, toString
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Method Detail

newLongRange

public static NumericRangeQuery<Long> newLongRange(String field,
                                                   int precisionStep,
                                                   Long min,
                                                   Long max,
                                                   boolean minInclusive,
                                                   boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a long range using the given precisionStep. You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newLongRange

public static NumericRangeQuery<Long> newLongRange(String field,
                                                   Long min,
                                                   Long max,
                                                   boolean minInclusive,
                                                   boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a long range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4). You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newIntRange

public static NumericRangeQuery<Integer> newIntRange(String field,
                                                     int precisionStep,
                                                     Integer min,
                                                     Integer max,
                                                     boolean minInclusive,
                                                     boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a int range using the given precisionStep. You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newIntRange

public static NumericRangeQuery<Integer> newIntRange(String field,
                                                     Integer min,
                                                     Integer max,
                                                     boolean minInclusive,
                                                     boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a int range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4). You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newDoubleRange

public static NumericRangeQuery<Double> newDoubleRange(String field,
                                                       int precisionStep,
                                                       Double min,
                                                       Double max,
                                                       boolean minInclusive,
                                                       boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a double range using the given precisionStep. You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. Double.NaN will never match a half-open range, to hit NaN use a query with min == max == Double.NaN. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newDoubleRange

public static NumericRangeQuery<Double> newDoubleRange(String field,
                                                       Double min,
                                                       Double max,
                                                       boolean minInclusive,
                                                       boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a double range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4). You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. Double.NaN will never match a half-open range, to hit NaN use a query with min == max == Double.NaN. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newFloatRange

public static NumericRangeQuery<Float> newFloatRange(String field,
                                                     int precisionStep,
                                                     Float min,
                                                     Float max,
                                                     boolean minInclusive,
                                                     boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a float range using the given precisionStep. You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. Float.NaN will never match a half-open range, to hit NaN use a query with min == max == Float.NaN. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


newFloatRange

public static NumericRangeQuery<Float> newFloatRange(String field,
                                                     Float min,
                                                     Float max,
                                                     boolean minInclusive,
                                                     boolean maxInclusive)
Factory that creates a NumericRangeQuery, that queries a float range using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4). You can have half-open ranges (which are in fact </≤ or >/≥ queries) by setting the min or max value to null. Float.NaN will never match a half-open range, to hit NaN use a query with min == max == Float.NaN. By setting inclusive to false, it will match all documents excluding the bounds, with inclusive on, the boundaries are hits, too.


getTermsEnum

protected TermsEnum getTermsEnum(Terms terms,
                                 AttributeSource atts)
                          throws IOException
Description copied from class: MultiTermQuery
Construct the enumeration to be used, expanding the pattern term. This method should only be called if the field exists (ie, implementations can assume the field does exist). This method should not return null (should instead return TermsEnum.EMPTY if no terms match). The TermsEnum must already be positioned to the first matching term. The given AttributeSource is passed by the MultiTermQuery.RewriteMethod to provide attributes, the rewrite method uses to inform about e.g. maximum competitive boosts. This is currently only used by TopTermsRewrite

Specified by:
getTermsEnum in class MultiTermQuery
Throws:
IOException

includesMin

public boolean includesMin()
Returns true if the lower endpoint is inclusive


includesMax

public boolean includesMax()
Returns true if the upper endpoint is inclusive


getMin

public T getMin()
Returns the lower value of this range query


getMax

public T getMax()
Returns the upper value of this range query


getPrecisionStep

public int getPrecisionStep()
Returns the precision step.


toString

public String toString(String field)
Description copied from class: Query
Prints a query to a string, with field assumed to be the default field and omitted.

Specified by:
toString in class Query

equals

public final boolean equals(Object o)
Overrides:
equals in class MultiTermQuery

hashCode

public final int hashCode()
Overrides:
hashCode in class MultiTermQuery


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