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Posted to issues@drill.apache.org by "Cheolgoo Kang (JIRA)" <ji...@apache.org> on 2018/09/07 21:55:01 UTC
[jira] [Updated] (DRILL-6734) Unable to find value vector of path
`EXPR$0`, returning null instance.
[ https://issues.apache.org/jira/browse/DRILL-6734?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Cheolgoo Kang updated DRILL-6734:
---------------------------------
Summary: Unable to find value vector of path `EXPR$0`, returning null instance. (was: Unable to find )
> Unable to find value vector of path `EXPR$0`, returning null instance.
> ----------------------------------------------------------------------
>
> Key: DRILL-6734
> URL: https://issues.apache.org/jira/browse/DRILL-6734
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - JDBC
> Affects Versions: 1.14.0
> Environment: Apache Drill version 1.14.0 running on CentOS 7.0.1406.
> MySQL version 5.5.43 running on CentOS 6.4.
> MySQL connector/j version 5.1.44.
> Reporter: Cheolgoo Kang
> Priority: Major
>
> Expressions in a query against JDBC without alias returns null as their value.
> I was trying to run this sample query to retrieve count of a MySQL table connected to Drill through the RDBMS storage plugin:
> {code}
> select count(*) from ngmysql.information_schema.`PROCESSLIST`
> {code}
> which returns
> {code}
> EXPR$0
> -------------
> <null>
> {code}
> and you could find this warning from the log:
> {quote}
> Unable to find value vector of path `EXPR$0`, returning null instance.
> {quote}
> But it works fine if you give an alias to the expression like this:
> {code}
> select count(*) as num from ngmysql.information_schema.`PROCESSLIST`;
> {code}
> which would end up giving this:
> {code}
> num
> ----------------------
> 16
> {code}
> Here's the portion of logs regarding the sample query:
> {code}
> 2018-09-07 21:44:52,709 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:foreman] INFO o.a.drill.exec.work.foreman.Foreman - Query text for query id 246d0eaa-f8e6-9536-af0c-1df3932cce9f: select count(*) from ngmysql.information_schema.`PROCESSLIST`
> 2018-09-07 21:44:52,752 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:frag:0:0] INFO o.a.d.e.w.fragment.FragmentExecutor - 246d0eaa-f8e6-9536-af0c-1df3932cce9f:0:0: State change requested AWAITING_ALLOCATION --> RUNNING
> 2018-09-07 21:44:52,753 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:frag:0:0] INFO o.a.d.e.w.f.FragmentStatusReporter - 246d0eaa-f8e6-9536-af0c-1df3932cce9f:0:0: State to report: RUNNING
> 2018-09-07 21:44:52,756 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:frag:0:0] WARN o.a.d.e.e.ExpressionTreeMaterializer - Unable to find value vector of path `EXPR$0`, returning null instance.
> 2018-09-07 21:44:52,759 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:frag:0:0] INFO o.a.d.e.w.fragment.FragmentExecutor - 246d0eaa-f8e6-9536-af0c-1df3932cce9f:0:0: State change requested RUNNING --> FINISHED
> 2018-09-07 21:44:52,760 [246d0eaa-f8e6-9536-af0c-1df3932cce9f:frag:0:0] INFO o.a.d.e.w.f.FragmentStatusReporter - 246d0eaa-f8e6-9536-af0c-1df3932cce9f:0:0: State to report: FINISHED
> {code}
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