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Posted to issues@ignite.apache.org by "Vladimir Ozerov (JIRA)" <ji...@apache.org> on 2019/02/14 15:32:00 UTC

[jira] [Resolved] (IGNITE-8591) SQL: Sort links on index pages in physical page order before row access

     [ https://issues.apache.org/jira/browse/IGNITE-8591?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vladimir Ozerov resolved IGNITE-8591.
-------------------------------------
    Resolution: Won't Fix

Not relevant at the moment.

> SQL: Sort links on index pages in physical page order before row access
> -----------------------------------------------------------------------
>
>                 Key: IGNITE-8591
>                 URL: https://issues.apache.org/jira/browse/IGNITE-8591
>             Project: Ignite
>          Issue Type: Task
>          Components: sql
>    Affects Versions: 2.5
>            Reporter: Vladimir Ozerov
>            Assignee: Vladimir Ozerov
>            Priority: Major
>              Labels: performance
>
> When index page match condition, we eagerly read all matched data rows. This leads to a number of random disk reads.as Ignite use heap-organized storage. We can pre-sort all matched row links in accordance to their physical location, and then read them in batch. This will give us two important advantages:
> 1) Data reads will be more sequential, this is especially important for HDDs
> 2) This could decrease number of page reads in case of dense data placement, because there will be less evictions.
> In future we should expand this optimization to several index pages in the same way it is done in major databases. 



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