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https://issues.apache.org/jira/browse/SOLR-1321?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12753648#action_12753648
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Andrzej Bialecki commented on SOLR-1321:
-----------------------------------------
This comment refers to the limitation of Lucene's QueryParser - there is only a
single flag there to decide whether it accepts leading wildcards or not,
regardless of field. Consequently, after checking the schema in SolrQueryParser
we turn on this flag if _any_ field type supports leading wildcards. The end
effect of this is that parsers for any field, which are created with
IndexSchema.getSolrQueryParser(), will return true if any field type supports
leading wildcards, not neccessarily the one for which the parser was created..
I don't see a way to fix this. I can clarify the comment, though, so that it's
clear that this is a limitation in Lucene QueryParser.
> Support for efficient leading wildcards search
> ----------------------------------------------
>
> Key: SOLR-1321
> URL: https://issues.apache.org/jira/browse/SOLR-1321
> Project: Solr
> Issue Type: Improvement
> Components: Analysis
> Affects Versions: 1.4
> Reporter: Andrzej Bialecki
> Assignee: Grant Ingersoll
> Fix For: 1.4
>
> Attachments: SOLR-1321.patch, wildcards-2.patch, wildcards-3.patch,
> wildcards.patch
>
>
> This patch is an implementation of the "reversed tokens" strategy for
> efficient leading wildcards queries.
> ReversedWildcardsTokenFilter reverses tokens and returns both the original
> token (optional) and the reversed token (with positionIncrement == 0).
> Reversed tokens are prepended with a marker character to avoid collisions
> between legitimate tokens and the reversed tokens - e.g. "DNA" would become
> "and", thus colliding with the regular term "and", but with the marker
> character it becomes "\u0001and".
> This TokenFilter can be added to the analyzer chain that it used during
> indexing.
> SolrQueryParser has been modified to detect the presence of such fields in
> the current schema, and treat them in a special way. First, SolrQueryParser
> examines the schema and collects a map of fields where these reversed tokens
> are indexed. If there is at least one such field, it also sets
> QueryParser.setAllowLeadingWildcards(true). When building a wildcard query
> (in getWildcardQuery) the term text may be optionally reversed to put
> wildcards further along the term text. This happens when the field uses the
> reversing filter during indexing (as detected above), AND if the wildcard
> characters are either at 0-th or 1-st position in the term. Otherwise the
> term text is processed as before, i.e. turned into a regular wildcard query.
> Unit tests are provided to test the TokenFilter and the query parsing.
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