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https://issues.apache.org/jira/browse/LUCENE-4376?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13453558#comment-13453558
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Jack Krupansky commented on LUCENE-4376:
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I don't see how the filter from LUCENE-3593 would be used within a Query.
As an example, derived from a recent email inquiry, the user may enter a query
such as:
{code}
foo bar AND imageUrl:*
{code}
Meaning, find documents with those two keywords where the imageUrl field is not
empty.
Sure, if they are writing raw Lucene they can manually apply the filter, but I
want to have that filtering applied within the Query.
Further, maybe only a much smaller subset of documents meet the non-empty
filter requirement. I would want the Query to be as fast as possible.
> Add Query subclasses for selecting documents where a field is empty or not
> --------------------------------------------------------------------------
>
> Key: LUCENE-4376
> URL: https://issues.apache.org/jira/browse/LUCENE-4376
> Project: Lucene - Core
> Issue Type: Improvement
> Components: core/query/scoring
> Reporter: Jack Krupansky
> Fix For: 5.0
>
>
> Users frequently wish to select documents based on whether a specified
> sparsely-populated field has a value or not. Lucene should provide specific
> Query subclasses that optimize for these two cases, rather than force users
> to guess what workaround might be most efficient. It is simplest for users to
> use a simple pure wildcard term to check for non-empty fields or a negated
> pure wildcard term to check for empty fields, but it has been suggested that
> this can be rather inefficient, especially for text fields with many terms.
> 1. Add NonEmptyFieldQuery - selects all documents that have a value for the
> specified field.
> 2. Add EmptyFieldQuery - selects all documents that do not have a value for
> the specified field.
> The query parsers could turn a pure wildcard query (asterisk only) into a
> NonEmptyFieldQuery, and a negated pure wildcard query into an EmptyFieldQuery.
> Alternatively, maybe PrefixQuery could detect pure wildcard and automatically
> "rewrite" it into NonEmptyFieldQuery.
> My assumption is that if the actual values of the field are not needed,
> Lucene can much more efficiently simply detect whether values are present,
> rather than, for example, the user having to create a separate boolean "has
> value" field that they would query for true or false.
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