Affects Version/s: Lucene.Net 5.0 PCL
Fix Version/s: None
Component/s: Lucene.Net Core
Originally we used Lucene 2.3 in the project for years.
Some time ago we made an update to the 5.0.0 version of Lucene.
After that Chinese analyzing stopped working normally (I did not test it on Japanese or Korean)
We have the following code to process the search request:
1. analyzer = new ClassicAnalyzer();
3. QueryParser qp = new QueryParser(fieldName, analyzer);
4. Query query = qp.parse(queryString);
6. int hits = searcher.search(query, 1).totalHits;
Analyzer on line 1 could be changed by config.
Line 2 is printing what we put to the Lucene.
Line 5 is printing how the query modified in Lucene
Normally we are using the string 打不开~0.7 for 70% or more accuracy and 打不开 to find exact this word.
~0.7 functionality was marked as deprecated since 4.0 version, however it is still worked on English at least.
What was before (on Lucene 2.3):
Line 2: 打不开~0.7
Line 5: 打不开~0.7
If we provide the correct string for analysis, line 6 returns correct result
The same for case of 打不开 without accuracy (without ~0.7)
What is now (on Lucene 5.0):
Line 2: 打不开~0.7
Line 5: 打不开~0
As I understood it is modifying of deprecated parameter to newly supported one with a little different meaning (at least it is working like I said on English).
The string for analysis contains the 打不开, however line 6 shows nothing is found.
Line 2: 打不开
Line 5: 打 不 开
Lucene added spaces, which are interpreted as OR operator. As result Line 6 returns that keyword found even if it is only one 不 symbol in the string for analysis.
The same scenario was tested on the CJKAnalyzer, ClassicAnalyzer and SmartChineseAnalyzer. Results are the same: neither one of them has the same functionality as analyzer on Lucene 2.3
Is it known problem in the product? Could you please explain or provide any docs about how the search should work for Chinese in mentioned cases.