[
https://issues.apache.org/jira/browse/LUCENE-5803?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Uwe Schindler updated LUCENE-5803:
----------------------------------
Attachment: LUCENE-5803.patch
Patch.
I added more Javadocs and tried to work around the stupid problem with the
super constructor call cannot reference to {{this}}. There is the possibibility
to do this by using the passed-in Analyzer, but then we loose the check
throwing the IllegalStateException.
We need this check, otherwise you would be able to corrumpt your analyzers: If
you wrap this analyzer again with some other analyzer that uses the delegate
reuse strategy, e.g., {{new ShingleAnalysisWrapper(new
PerFieldAnalyzerWrapper(....))}}, the ShingleAnalysisWrapper would reuse the
PerFieldAnalyzerWrapper's strategy (which is private to the PerFieldAnalysis
wrapper) and by that inject illegal TokenStreamComponents into the inner's
cache. So we must disallow this.
This patch misses some tests for this special case and also to test if
everything works fine.
Solr is also using this Analyzer, so we see the improvements in Solr, too (not
only in Elasticsearch). In fact, PER_FIELD_REUSE_STRATEGY is no longer used for
pure per-field delegates. We no longer have one TokenStream instance per field,
we have one instance per delegate Analyzer.
> Add another AnalyzerWrapper class that does not have its own cache, so
> delegate-only wrappers don't create thread local resources several times
> -----------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-5803
> URL: https://issues.apache.org/jira/browse/LUCENE-5803
> Project: Lucene - Core
> Issue Type: Improvement
> Components: modules/analysis
> Affects Versions: 4.9
> Reporter: Uwe Schindler
> Assignee: Uwe Schindler
> Fix For: 5.0, 4.10
>
> Attachments: LUCENE-5803.patch
>
>
> This is a followup issue for the following Elasticsearch issue:
> https://github.com/elasticsearch/elasticsearch/pull/6714
> Basically the problem is the following:
> - Elasticsearch has a pool of Analyzers that are used for analysis in several
> indexes
> - Each index uses a different PerFieldAnalyzerWrapper
> PerFieldAnalyzerWrapper uses PER_FIELD_REUSE_STRATEGY. Because of this it
> caches the tokenstreams for every field. If there are many fields, this are a
> lot. In addition, the underlying analyzers may also cache tokenstreams and
> other PerFieldAnalyzerWrappers do the same, although the delegate Analyzer
> can always return the same components.
> We should add similar code to Elasticsearch's directly to Lucene: If the
> delegating Analyzer just delegates per Field or just wraps CharFilters around
> the Reader, there is no need to cache the TokenStreamComponents a second time
> in the delegating Analyzers. This is only needed, if the delegating Analyzers
> adds additional TokenFilters (like ShingleAnalyzerWrapper).
> We should name this new class DelegatingAnalyzerWrapper extends
> AnalyzerWrapper. The wrapComponents method must be final, because we are not
> allowed to add additional TokenFilters, but unlike ES, we don't need to
> disallow wrapping with CharFilters.
> Internally this class uses a private ReuseStrategy that just delegates to the
> underlying analyzer. It does not matter here if the strategy of the delegate
> is global or per field, this is private to the delegate.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
