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From: Xi Yang <alex.xi.yang@gmail.com>
Date: Tue, 7 Mar 2017 16:43:16 -0800
Message-ID: <CAGyfEV_GTXGk0as9xLj5BwOLSxkVpgFLLvmHcOJGNfOv1krF8A@mail.gmail.com>
Subject: Re: What if I want to write another table in MasterObserver.preModifyColumnFamily
 ?
To: dev@hbase.apache.org
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archived-at: Wed, 08 Mar 2017 00:43:22 -0000

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Requirement:

I want to record every change of modify columnFamily by using
preModifyColumnFamily().
Now I have a table "my_ddl_log" which used to record the change of
columnFamily. For example:

If jack change the TTL of columnFamily "primary" in table "employee". Then
we should add a put to "my_ddl_log" like this record:
log:name= 'jack'
log:updateTime= '2017-03-07 12:12 GMT-08:00'
log:change= ''Change TTL of Table: employee ColumnFamily: primary'

I try to use preModifyColumnFamily to do this stuff.

Thanks,
Alex


2017-03-07 12:12 GMT-08:00 Ted Yu <yuzhihong@gmail.com>:

> Describing your use case would allow people to give better answer.
>
> What kind of data do you write to other table in preModifyColumnFamily() ?
>
> Cross server call within observer is not good idea.
>
> Take a look at ConnectionUtils.createShortCircuitConnection().
>
> Cheers
>
> On Tue, Mar 7, 2017 at 11:42 AM, Xi Yang <alex.xi.yang@gmail.com> wrote:
>
> >     All the articles I've ever seen are talking about add increment or
> > change put/get status or pinrt out logs. what if I want to write some
> data
> > to another table in Observer? For
> > example, MasterObserver.preModifyColumnFamily()? Seems Observer is
> runing
> > at server side, so use connection is unneccessary and might raise some
> > problem.
> >    I know this might be a stupid question, so if you can just give some
> > links let me to learn without explain in email, I will be grateful to you
> > for your help
> >
> > Thanks,
> > Alex
> >
>

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