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From Pradeep Kumbhar <prad...@datatorrent.com>
Subject Re: APEXMALHAR-2382 User needs to create dt_meta table while using JdbcPOJOInsertOutputOperator
Date Mon, 16 Jan 2017 05:46:08 GMT
+1 on having operator documentation explicitly mentioning that, "dt_meta"
table is mandatory
for the operator to work correctly. Also provide a sample table creation
query for reference.

On Sat, Jan 14, 2017 at 1:05 PM, AJAY GUPTA <ajaygit158@gmail.com> wrote:

> Since the query can be different for different databases, the user will
> have to provide query to the operator. Rather than this, I believe it's
> easier for user to directly execute create table query on DB.
>
> Also, the create table script won't be that heavy that we create script for
> it. Probably adding a generic type of query in the docs itself should
> suffice.
>
>
> Ajay
>
> On Sat, 14 Jan 2017 at 10:27 AM, Yogi Devendra <yogidevendra@apache.org>
> wrote:
>
> > As Aniruddha pointed out, table creation should be done by dbadmin.
> >
> > In that case, utility script will be helpful.
> >
> >
> >
> > If we embed this code inside operator or application; then it will be
> >
> > difficult for dbadmin to use it.
> >
> >
> >
> > ~ Yogi
> >
> >
> >
> > On 14 January 2017 at 03:43, Thomas Weise <thw@apache.org> wrote:
> >
> >
> >
> > > -1 for automatic schema modification, unless the user asked for it. See
> >
> > > comment on JIRA.
> >
> > >
> >
> > >
> >
> > > On Fri, Jan 13, 2017 at 5:11 AM, Aniruddha Thombare <
> >
> > > aniruddha@datatorrent.com> wrote:
> >
> > >
> >
> > > > The tables should be created / altered by dbadmin.
> >
> > > > We shouldn't worry about table creations as its one-time activity.
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > Thanks,
> >
> > > >
> >
> > > > A
> >
> > > >
> >
> > > >
> >
> > > > _____________________________________
> >
> > > > Sent with difficulty, I mean handheld ;)
> >
> > > >
> >
> > > > On 13 Jan 2017 6:37 pm, "Yogi Devendra" <yogidevendra@apache.org>
> > wrote:
> >
> > > >
> >
> > > > I am not very keen on having utility script.
> >
> > > > But, "no side-effects without explicit ask by the end-user" is
> > important.
> >
> > > >
> >
> > > > ~ Yogi
> >
> > > >
> >
> > > > On 13 January 2017 at 16:44, Priyanka Gugale <priyag@apache.org>
> > wrote:
> >
> > > >
> >
> > > > > IMO it's okay to create table in java code. We should document it
> in
> >
> > > > > operator guide as well as put a log message when we create table.
> >
> > > > > And in case you don't have privileges, the operator should throw
> >
> > > > meaningful
> >
> > > > > message.
> >
> > > > >
> >
> > > > > -Priyanka
> >
> > > > >
> >
> > > > > On Fri, Jan 13, 2017 at 4:07 PM, Yogi Devendra <
> >
> > > yogidevendra@apache.org>
> >
> > > > > wrote:
> >
> > > > >
> >
> > > > > > My suggestions:
> >
> > > > > >
> >
> > > > > >    1. Have a separate utility script for creating this table.
> >
> > > > > >    2. Have README for the utility script
> >
> > > > > >    3. Mention about the utility script in the operator javadocs.
> >
> > > > > >    4. Mention  about the utility script in the application
> README.
> >
> > > > > >    5. If at all, you wish to ease out the process; you can
> > introduce
> >
> > > > flag
> >
> > > > > >    like autoPopulateMetaTable. But. default value of this flag
> > should
> >
> > > > to
> >
> > > > > be
> >
> > > > > >    off.
> >
> > > > > >    6. I would prefer to avoid side-effects unless explicitly
> asked
> > by
> >
> > > > the
> >
> > > > > >    end user.
> >
> > > > > >    7. Relevant exceptions should be caught and should have a
> > message
> >
> > > > > which
> >
> > > > > >    can be understood by the end user.
> >
> > > > > >
> >
> > > > > > ~ Yogi
> >
> > > > > >
> >
> > > > > > On 13 January 2017 at 15:57, Hitesh Kapoor <
> hitesh@datatorrent.com
> > >
> >
> > > > > wrote:
> >
> > > > > >
> >
> > > > > > > Hi All,
> >
> > > > > > >
> >
> > > > > > > Currently to use JdbcPOJOInsertOutputOperator, user needs
to
> > create
> >
> > > > > > > "dt_meta" table to enforce
> >
> > > > > > > exactly-once processing semantic. If the user fails to
create
> > this
> >
> > > > > table
> >
> > > > > > > before launching the application an exception is thrown.
> >
> > > > > > > To handle this scenario we can automate the process of
creating
> >
> > > this
> >
> > > > > > table,
> >
> > > > > > > assuming the user has the appropriate privileges. The problem
> > with
> >
> > > > this
> >
> > > > > > > approach is that it may not be a very good idea to modify
> user's
> >
> > > > > database
> >
> > > > > > > automatically , also if the user doesn't has the appropriate
> >
> > > > privileges
> >
> > > > > > it
> >
> > > > > > > will eventually throw an exception (however a different
> > exception).
> >
> > > > > > > So I need your opinion if we should automate the creation
of
> this
> >
> > > > > > internal
> >
> > > > > > > table (if it doesn't exists) or continue with the existing
> >
> > > behaviour
> >
> > > > or
> >
> > > > > > > anything else.
> >
> > > > > > >
> >
> > > > > > > Regards,
> >
> > > > > > > Hitesh
> >
> > > > > > >
> >
> > > > > >
> >
> > > > >
> >
> > > >
> >
> > >
> >
> >
>



-- 
*regards,*
*~pradeep*

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