[teiid-issues] [JBoss JIRA] (TEIID-4455) Impala Translator - Change planning step for from_unixtime() pushdown

[Jan Stastny (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-4455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13625145#comment-13625145 ] 

Jan Stastny commented on TEIID-4455:
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[~shawkins] I believe that direct pushdown is incorrect.

On impala and hive the return type of from_unixtime is string, which is not conveying the timezone information. (By default the values are considered to be in UTC timezone, but this can be tweaked at least in impala by a property '-use_local_tz_for_unix_timestamp_conversions' when starting the instance.)

Teiid does not account for the timezone difference between source and running instance (ignores DatabaseTimeZone property). It is serving exactly the same timestamp as received from hive/impala instance, even though there's timezone difference.

> Impala Translator - Change planning step for from_unixtime() pushdown
> ---------------------------------------------------------------------
>
>                 Key: TEIID-4455
>                 URL: https://issues.jboss.org/browse/TEIID-4455
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: JDBC Connector
>            Reporter: Don Krapohl
>            Assignee: Kylin Soong
>            Priority: Minor
>              Labels: Impala_Translator
>             Fix For: 9.2, 8.12.15.6_4
>
>
> Impala and Teiid both have from_unixtime() functions and per the forum reference the mapping to timestampadd() appears to come before the test for pushdown support of the impala native function.
> As a query request we require the impala from_unixtime() function be executed instead of the Teiid-native version.



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