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From "Steven Jacobs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ASTERIXDB-1606) Optimize "last value" query
Date Tue, 23 Aug 2016 21:33:21 GMT

    [ https://issues.apache.org/jira/browse/ASTERIXDB-1606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15433653#comment-15433653
] 

Steven Jacobs commented on ASTERIXDB-1606:
------------------------------------------

This will be great to have in master. What are your thoughts on (1)?

> Optimize "last value" query
> ---------------------------
>
>                 Key: ASTERIXDB-1606
>                 URL: https://issues.apache.org/jira/browse/ASTERIXDB-1606
>             Project: Apache AsterixDB
>          Issue Type: Bug
>            Reporter: Steven Jacobs
>            Priority: Minor
>
> We need to work on optimizing queries looking for a "most recent" or "greatest" value
of a given field. 
> As an example, consider an append-only dataset filled with user locations over time,
and suppose we want to know the user's last known location. Currently, we would need to do
this as an:
> order by $record.timeStamp
> limit 1
> We could improve this in two ways:
> 1) Improve usability by providing an alias syntax for users, e.g. "where greatest timeStamp"
> 2) Improve the compilation of such a job to only retrieve a single record.



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