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From "Vladimir Ozerov (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (IGNITE-4150) B-Tree index cannot be used efficiently with IN clause.
Date Tue, 14 Aug 2018 15:00:00 GMT

    [ https://issues.apache.org/jira/browse/IGNITE-4150?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16579920#comment-16579920
] 

Vladimir Ozerov commented on IGNITE-4150:
-----------------------------------------

One more TC before merge to master: https://ci.ignite.apache.org/viewType.html?buildTypeId=IgniteTests24Java8_RunAllSql

> B-Tree index cannot be used efficiently with IN clause.
> -------------------------------------------------------
>
>                 Key: IGNITE-4150
>                 URL: https://issues.apache.org/jira/browse/IGNITE-4150
>             Project: Ignite
>          Issue Type: Task
>          Components: sql
>    Affects Versions: 1.7
>            Reporter: Vladimir Ozerov
>            Assignee: Taras Ledkov
>            Priority: Major
>              Labels: performance, sql-stability
>             Fix For: 2.7
>
>
> Consider the following query:
> {code}
> SELECT * FROM table
> WHERE a = ? AND b IN (?, ?)
> {code}
> If there is an index {{(a, b)}}, it will not be used properly: only column {{a}} will
be used. This will leads to multiple unnecessary comparisons.
> Most obvious way to fix that - use temporary table and {{JOIN}}. However, this approach
doesn't work well when there are multiple {{IN}}'s. 
> Proper solution would be to hack deeper into H2.



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