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https://issues.apache.org/jira/browse/CARBONDATA-2747?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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jiangmanhua updated CARBONDATA-2747:
------------------------------------
    Summary: Fix Lucene datamap choosing  and DataMapDistributable building  
(was: Lucene build wrong DataMapDistributable for all datamaps with same 
DataMapSchema)

> Fix Lucene datamap choosing  and DataMapDistributable building
> --------------------------------------------------------------
>
>                 Key: CARBONDATA-2747
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-2747
>             Project: CarbonData
>          Issue Type: Bug
>            Reporter: jiangmanhua
>            Priority: Major
>
> similar problem in bloom datamap is in issue CARBONDATA-2746; but test result 
> is wrong  if we apply same fix
>  
> Analysis:
> In `DataMapChooser#extractColumnExpression`, it does not deal with 
> `MatchExpression`. This makes no information to use the column name to filter 
> datamap.
>  
> In `DataMapChooser#contains`, all datamap are marked as useful if lucene 
> datamap is hit ( `ExpressionType.TEXT_MATCH`). Then the first datamap is 
> chosen after sort step(sort by number of index column) . 
>  
> In `LuceneDataMapFactoryBase#toDistributable`, carbon getAllIndexDirs and 
> build DataMapDistributable for each index in same segment. This means that 
> one segment will be applied `prune` by different index datamap(lucene use 
> `indexPath` in `LuceneDataMapDistributable` to init its datamap object and 
> build the `indexSearcherMap`)
>  
> In out test case, we build datamaps  on columns:name and city, one for each.
> Query uses column `name` as filter. Unfortunately, in the `DataMapChooser`, 
> it chooses datamap of city column.
> Then in `toDistributable` method, it gets all datamaps and build 
> `LuceneDataMapDistributable`. Here in out test, it will prune and get result 
> from each datamap.
> On datamap of city, query "name:c10"  in lucene return no row. On datamap of 
> name, query "name:c10"  in lucene return actual what we want.
>  
> So, if we apply same fix in CARBONDATA-2746 for lucene,  we will get only one 
> datamap ( which is for city column) and prune result will be nothing.
>  
> To Fix:
>  # choose correct datamap in DataMapChooser for lucene
>  # apply same fix in CARBONDATA-2746 to build correct 
> `LuceneDataMapDistributable`



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