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https://issues.apache.org/jira/browse/LUCENE-6459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14543434#comment-14543434
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Michael McCandless commented on LUCENE-6459:
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bq. We should use this API for other suggesters, but maybe in a separate issue
Yes, definitely separate!
bq. In terms of new functionality, fuzzy, regex and context queries are added.
OK, cool, these are nice additions.
bq. query-time context boosts
Cool: so you boost some contexts more than others, using ContextQuery.
bq. As we only allow integer index-time weights
I thought we accept long (not int) as index-time weight? (But, I
think that really is overkill... maybe they should just floats, like
per-field boosting at index time). But we can worry about this
later...
bq. one possibility would be to use index-weight + (Int.MAX * boost) instead of
using MaxWeight of suggestions
Sorry I don't understand the idea here?
{quote}
bq. If you try to use ContextQuery against a field that you had not indexed
contexts with (using ContextSuggestField) do you see any error? Maybe this is
too hard.
There should not be any error. A ContextQuery will never be run on a
SuggestField
{quote}
It seems like we could detect this mis-use, since CompletionTerms seems to know
whether the field was indexed with contexts or not? I.e, if I accidentally try
to run a ContextQuery against a field indexed with only SuggestField, it seems
like I should get an exception saying I screwed up ... (similar to trying to
run a PhraseQuery on a field that did not index positions)? Maybe add a simple
test case?
{quote}
A ContextQuery will never be run on a SuggestField,
CompletionQuery rewrites appropriately given the type of the field
(context-enabled or not).
{quote}
OK maybe at that rewrite is the time to throw the exc?
{quote}
This also makes non-context queries work as expected when run against
ContextSuggestField
(as in the query is wrapped as a ContextQuery with no context
filtering/boosting).
{quote}
OK, for that direction it makes sense allow ... good.
{quote}
bq. Are you allowed to mix ContextSuggestField and SuggestField even for the
same field name, within one suggester?
No you are not. If mixed, CompletionFieldsConsumer will throw
IllegalArgumentException upon indexing.
{quote}
OK, excellent.
Can we rename {{TopSuggestDocsCollector.num()}} to maybe .getCountToCollect or
something a bit more verbose?
Net/net this is a nice change, thanks [~areek]!
> [suggest] Query Interface for suggest API
> -----------------------------------------
>
> Key: LUCENE-6459
> URL: https://issues.apache.org/jira/browse/LUCENE-6459
> Project: Lucene - Core
> Issue Type: New Feature
> Components: core/search
> Affects Versions: 5.1
> Reporter: Areek Zillur
> Assignee: Areek Zillur
> Fix For: Trunk, 5.x, 5.1
>
> Attachments: LUCENE-6459.patch, LUCENE-6459.patch, LUCENE-6459.patch,
> LUCENE-6459.patch, LUCENE-6459.patch, LUCENE-6459.patch
>
>
> This patch factors out common indexing/search API used by the recently
> introduced [NRTSuggester|https://issues.apache.org/jira/browse/LUCENE-6339].
> The motivation is to provide a query interface for FST-based fields
> (*SuggestField* and *ContextSuggestField*) for enabling suggestion scoring
> and more powerful automaton queries.
> Previously, only prefix ‘queries’ with index-time weights were supported but
> we can also support:
> * Prefix queries expressed as regular expressions: get suggestions that
> match multiple prefixes
> ** Example: _star\[wa\|tr\]_ matches _starwars_ and _startrek_
> * Fuzzy Prefix queries supporting scoring: get typo tolerant suggestions
> scored by how close they are to the query prefix
> ** Example: querying for _seper_ will score _separate_ higher then
> _superstitious_
> * Context Queries: get suggestions boosted and/or filtered based on their
> indexed contexts (meta data)
> ** Example: get typo tolerant suggestions on song names with prefix _like
> a roling_ boosting songs with genre _rock_ and _indie_
> ** Example: get suggestion on all file names starting with _finan_ only
> for _user1_ and _user2_
> h3. Suggest API
> {code}
> SuggestIndexSearcher searcher = new SuggestIndexSearcher(reader);
> CompletionQuery query = ...
> TopSuggestDocs suggest = searcher.suggest(query, num);
> {code}
> h3. CompletionQuery
> *CompletionQuery* is used to query *SuggestField* and *ContextSuggestField*.
> A *CompletionQuery* produces a *CompletionWeight*, which allows
> *CompletionQuery* implementations to pass in an automaton that will be
> intersected with a FST and allows boosting and meta data extraction from the
> intersected partial paths. A *CompletionWeight* produces a
> *CompletionScorer*. A *CompletionScorer* executes a Top N search against the
> FST with the provided automaton, scoring and filtering all matched paths.
> h4. PrefixCompletionQuery
> Return documents with values that match the prefix of an analyzed term text
> Documents are sorted according to their suggest field weight.
> {code}
> PrefixCompletionQuery(Analyzer analyzer, Term term)
> {code}
> h4. RegexCompletionQuery
> Return documents with values that match the prefix of a regular expression
> Documents are sorted according to their suggest field weight.
> {code}
> RegexCompletionQuery(Term term)
> {code}
> h4. FuzzyCompletionQuery
> Return documents with values that has prefixes within a specified edit
> distance of an analyzed term text.
> Documents are ‘boosted’ by the number of matching prefix letters of the
> suggestion with respect to the original term text.
> {code}
> FuzzyCompletionQuery(Analyzer analyzer, Term term)
> {code}
> h5. Scoring
> {{suggestion_weight + (global_maximum_weight * boost)}}
> where {{suggestion_weight}}, {{global_maximum_weight}} and {{boost}} are all
> integers.
> {{boost = # of prefix characters matched}}
> h4. ContextQuery
> Return documents that match a {{CompletionQuery}} filtered and/or boosted by
> provided context(s).
> {code}
> ContextQuery(CompletionQuery query)
> contextQuery.addContext(CharSequence context, int boost, boolean exact)
> {code}
> *NOTE:* {{ContextQuery}} should be used with {{ContextSuggestField}} to query
> suggestions boosted and/or filtered by contexts
> h5. Scoring
> {{suggestion_weight + (global_maximum_weight * context_boost)}}
> where {{suggestion_weight}}, {{global_maximum_weight}} and {{context_boost}}
> are all integers
> When used with {{FuzzyCompletionQuery}},
> {{suggestion_weight + (global_maximum_weight * (context_boost +
> fuzzy_boost))}}
> h3. Context Suggest Field
> To use {{ContextQuery}}, use {{ContextSuggestField}} instead of
> {{SuggestField}}. Any {{CompletionQuery}} can be used with
> {{ContextSuggestField}}, the default behaviour is to return suggestions from
> *all* contexts. {{Context}} for every completion hit can be accessed through
> {{SuggestScoreDoc#context}}.
> {code}
> ContextSuggestField(String name, Collection<CharSequence> contexts, String
> value, int weight)
> {code}
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