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https://issues.apache.org/jira/browse/LUCENE-1345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662796#action_12662796
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Uwe Schindler commented on LUCENE-1345:
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{quote}
bq. In my opinion, the terms "Query" and "Filter" should be merged.
There is clear distinction between the two terms.
QueryWrapperFilter changes a Query into a Filter and ConstantScoreQuery changes
a Filter into a Query.
The first one removes the scoring by upcasting a Scorer to a DocIdSetIterator,
and the second one adds a constant score to a DocIdSetIterator to create a
Scorer.
{quote}
You are right, but for a Lucene user there is always the problem of the
distiction between both terms. When combining both, the user would get less
burden on thinking about both. It would make life easier, and would hide some
work for the user. The problem are the fine differences between the both, but
for the general user who does not have such large indexes where the difference
between both counts, it would makte things easier.
How about merging Filters and Queries and then thinking about optimizations in
the code of BooleanQuery to identify use cases where the scoring can be removed
and where a constant score is needed. There are two cases where the two
different types make problems:
- user (A) wants to use my contrib TrieRangeQuery/-Filter and just execute a
Query that returns documents that match the Range. The problem for this user
is: How to implement this? User a MatchAllDocsQuery and filter the results with
TrieRangeFilter or use ConstantScoreQuery to combine both? What is faster?
- user (B) wants to filter some documents using a normal Filter. If he uses the
standard Query+Filter combination of Searcher.search() he must before
distinguish what part of the combinations should be the filter and what should
be the query. Maybe he got a TrieRangeQuery (the query one using a
ConstantScore on the Filter) as query and want it combine with another query.
With the new code that detects the type of both clauses, BooleanQuery code
could choose to execute the TermQueries as normal scorer query and filter the
results using the given Filter as clause.
Both tasks could be easily combined if Query and Filter would be the same. The
user (A) would not need to create a constant score query on the Trie filter, he
could just use it with Searcher.search() as a "Query". If he want to add some
normal term queries from a query parser to it, he would use a BooleanQuery to
combine both. The BooleanQuery code would then find out that one of the clauses
is a Filter and would *not* use ConstantScore code to filter the result and
just use the normal filter code. For the user it is simplier: He would always
create a TrieRangeQueryFilter combination and would let BooleanQuery choose
what query execution strategy to use.
> Allow Filter as clause to BooleanQuery
> --------------------------------------
>
> Key: LUCENE-1345
> URL: https://issues.apache.org/jira/browse/LUCENE-1345
> Project: Lucene - Java
> Issue Type: Improvement
> Components: Search
> Reporter: Paul Elschot
> Priority: Minor
> Fix For: 2.9
>
> Attachments: booleansetperf.txt, DisjunctionDISI.java,
> DisjunctionDISI.patch, DisjunctionDISI.patch,
> LUCENE-1345-Filter+Query-merge.patch, LUCENE-1345.patch, LUCENE-1345.patch,
> OpenBitSetIteratorExperiment.java, TestIteratorPerf.java,
> TestIteratorPerf.java
>
>
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