[teiid-issues] [JBoss JIRA] (TEIID-3957) Impala translator - Add pushdown of offset in LIMIT clause to overcome difference in LIMIT clause

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-3957?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins updated TEIID-3957:
----------------------------------
       Issue Type: Enhancement  (was: Bug)
    Fix Version/s: 9.0


> BUT this means give me 25 rows starting from *PAGE * 76 (with page size of 25 rows)

I don't see that meaning in the docs.  It appears to just be a standard offset after which a limit is applied.

> The Teiid Impala translator doesn't push the offset but sums the limit and offset

Yes, that is the standard compensation when the translator is not marked as supporting offset.  I believe that this was initially the case because we were targeting early releases of impala.  It will be straight-forward to add support.

> Impala translator - Add pushdown of offset in LIMIT clause to overcome difference in LIMIT clause
> -------------------------------------------------------------------------------------------------
>
>                 Key: TEIID-3957
>                 URL: https://issues.jboss.org/browse/TEIID-3957
>             Project: Teiid
>          Issue Type: Enhancement
>          Components: JDBC Connector
>    Affects Versions: 8.12.4
>         Environment: Ubuntu Trusty
>            Reporter: Don Krapohl
>            Assignee: Steven Hawkins
>            Priority: Minor
>             Fix For: 9.0
>
>
> With the impala translator we issue this LIMIT to Teiid:
> ORDER BY somecolumn DESC LIMIT 75, 25
> this means give me 25 rows starting from *ROW* 76.
> In Impala's SQL this should be translated to:
> ORDER BY somecolumn DESC LIMIT 25 OFFSET 75
> BUT this means give me 25 rows starting from *PAGE * 76 (with page size of 25 rows)
> ref: http://www.cloudera.com/documentation/archive/impala/2-x/2-1-x/topics/impala_offset.html
> The Teiid Impala translator doesn't push the offset but sums the limit and offset:
> ORDER BY somecolumn DESC LIMIT 100
> Request we add pushdown, which will be more efficient and overcome the difference in how offsets are handled between Impala and Teiid.



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