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Posted to user@drill.apache.org by Nishith Kumar Nayak <na...@gmail.com> on 2017/03/16 14:39:27 UTC

Reg: Column name is not passed to RDBMS

Hi,

While trying to run SQL query for RDBMS source like Oracle, instead of the
column names from the table referred it it pushing down * to the respective
database.

Ex: Select empName from Employee

Passed to Oracle is

select * from Employee

For large scale application, it is fetching all the unnecessary columns
from the referred table.

Even i was trying to understand the physical query plan for the query.
After getting the whole result set through jdbc scan, it is trying to get
the column by projection.

Ideally it should push down the desired column name to database.

I am really stuck with this issue for my application.

Any suggestion or help is appreciated.

Regards,
Nishith Kumar Nayak

Re: Reg: Column name is not passed to RDBMS

Posted by Jinfeng Ni <jn...@apache.org>.
Can you please first check the EXPLAIN PLAN output for your query? The
first step is to figure out whether it's planner issue, or execution
issue.



On Thu, Mar 16, 2017 at 7:39 AM, Nishith Kumar Nayak
<na...@gmail.com> wrote:
> Hi,
>
> While trying to run SQL query for RDBMS source like Oracle, instead of the
> column names from the table referred it it pushing down * to the respective
> database.
>
> Ex: Select empName from Employee
>
> Passed to Oracle is
>
> select * from Employee
>
> For large scale application, it is fetching all the unnecessary columns
> from the referred table.
>
> Even i was trying to understand the physical query plan for the query.
> After getting the whole result set through jdbc scan, it is trying to get
> the column by projection.
>
> Ideally it should push down the desired column name to database.
>
> I am really stuck with this issue for my application.
>
> Any suggestion or help is appreciated.
>
> Regards,
> Nishith Kumar Nayak

Re: Reg: Column name is not passed to RDBMS

Posted by Jinfeng Ni <jn...@apache.org>.
Can you please first check the EXPLAIN PLAN output for your query? The
first step is to figure out whether it's planner issue, or execution
issue.



On Thu, Mar 16, 2017 at 7:39 AM, Nishith Kumar Nayak
<na...@gmail.com> wrote:
> Hi,
>
> While trying to run SQL query for RDBMS source like Oracle, instead of the
> column names from the table referred it it pushing down * to the respective
> database.
>
> Ex: Select empName from Employee
>
> Passed to Oracle is
>
> select * from Employee
>
> For large scale application, it is fetching all the unnecessary columns
> from the referred table.
>
> Even i was trying to understand the physical query plan for the query.
> After getting the whole result set through jdbc scan, it is trying to get
> the column by projection.
>
> Ideally it should push down the desired column name to database.
>
> I am really stuck with this issue for my application.
>
> Any suggestion or help is appreciated.
>
> Regards,
> Nishith Kumar Nayak