Alan Woodward 2571bf355f LUCENE-8477: Automatically rewrite disjunctions when internal gaps matter (#620)
We have a number of IntervalsSource implementations where automatic minimization of
disjunctions can lead to surprising results:

* PHRASE queries can miss matches because a longer matching sub-source is minimized
  away, leaving a gap
* MAXGAPS queries can miss matches for the same reason
* CONTAINING, NOT_CONTAINING, CONTAINED_BY and NOT_CONTAINED_BY queries
  can miss matches if the 'big' interval gets minimized

The proper way to deal with this is to rewrite the queries by pulling disjunctions to the top
of the query tree, so that PHRASE("a", OR(PHRASE("b", "c"), "c")) is rewritten to
OR(PHRASE("a", "b", "c"), PHRASE("a", "c")). To be able to do this generally, we need to
add a new pullUpDisjunctions() method to IntervalsSource that performs this rewriting
for each source that it would apply to.

Because these rewritten queries will in general be less efficient due to the duplication of
effort (eg the rewritten PHRASE query above pulls 5 term iterators rather than 4 in the
original), we also add an option to Intervals.or() that will prevent this happening, so that
consumers can choose speed over accuracy if it suits their usecase.
2019-03-27 11:24:29 +00:00
2017-09-20 15:31:25 -04:00
2010-12-12 15:36:08 +00:00

Apache Lucene and Solr

Apache Lucene is a high-performance, full featured text search engine library written in Java.

Apache Solr is an enterprise search platform written using Apache Lucene. Major features include full-text search, index replication and sharding, and result faceting and highlighting.

Online Documentation

This README file only contains basic setup instructions. For more comprehensive documentation, visit:

Building Lucene/Solr

(You do not need to do this if you downloaded a pre-built package.)

Lucene and Solr are built using Apache Ant. To build Lucene and Solr, run:

ant compile

If you see an error about Ivy missing while invoking Ant (e.g., .ant/lib does not exist), run ant ivy-bootstrap and retry.

Sometimes you may face issues with Ivy (e.g., an incompletely downloaded artifact). Cleaning up the Ivy cache and retrying is a workaround for most of such issues:

rm -rf ~/.ivy2/cache

The Solr server can then be packaged and prepared for startup by running the following command from the solr/ directory:

ant server

Running Solr

After building Solr, the server can be started using the bin/solr control scripts. Solr can be run in either standalone or distributed (SolrCloud mode).

To run Solr in standalone mode, run the following command from the solr/ directory:

bin/solr start

To run Solr in SolrCloud mode, run the following command from the solr/ directory:

bin/solr start -c

The bin/solr control script allows heavy modification of the started Solr. Common options are described in some detail in solr/README.txt. For an exhaustive treatment of options, run bin/solr start -h from the solr/ directory.

Development/IDEs

Ant can be used to generate project files compatible with most common IDEs. Run the ant command corresponding to your IDE of choice before attempting to import Lucene/Solr.

  • Eclipse - ant eclipse (See this for details)
  • IntelliJ - ant idea (See this for details)
  • Netbeans - ant netbeans (See this for details)

Running Tests

The standard test suite can be run with the command:

ant test

Like Solr itself, the test-running can be customized or tailored in a number or ways. For an exhaustive discussion of the options available, run:

ant test-help

Contributing

Please review the Contributing to Solr Guide for information on contributing.

Discussion and Support

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