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From Yang Zhang <zhang.yang...@gmail.com>
Subject Re: Coprocessor prePut
Date Tue, 23 Jan 2018 05:34:02 GMT
In fact, I prevent normal writes, and put the same data with a different
row key(Except row key, they have the same columns and same data).
I have already solved the infinite call by add and check some flag
attribute to Put. If the flag exist then skip my code.

This will prevent the infinite call of prePut(). But I want to know If
there are any method support by coprocessor context to do that.
Just like that you can call context.complete() to skip other coprocessors.

Thanks for your advice

2018-01-23 13:01 GMT+08:00 Ted Yu <yuzhihong@gmail.com>:

> Your prePut would write to a different column in the table, right ?
> Otherwise do you prevent normal writes from getting into the same column(s)
> ?
>
> If your prePut writes to dedicated column(s), you can check the presence of
> such column(s) so that the call is not infinite.
>
> Cheers
>
> On Mon, Jan 22, 2018 at 8:56 PM, Yang Zhang <zhang.yang.dm@gmail.com>
> wrote:
>
> > Yes, It is the same table.
> >
> > 2018-01-23 1:46 GMT+08:00 Ted Yu <yuzhihong@gmail.com>:
> >
> > > Can you clarify your use case ?
> > >
> > > bq. put a data into table
> > >
> > > Does your coprocessor write to the same table which receives user data
> ?
> > >
> > > Cheers
> > >
> > > On Mon, Jan 22, 2018 at 4:24 AM, Yang Zhang <zhang.yang.dm@gmail.com>
> > > wrote:
> > >
> > > > Hello Everyone
> > > >
> > > >         I am using the coprocessor and want to put another data when
> > > > someone put a data into table. So I try prePut(), but when you call
> > > > HRegion.put(), this will call my coprocessor's prePut function again,
> > and
> > > > it will cause an dead loop.
> > > >
> > > >         My code looks like below, If anyone know how to make HBase
> > call
> > > my
> > > > coprocessor just for the first time?
> > > >
> > > > @Override
> > > >     public void prePut(ObserverContext<RegionCoprocessorEnvironment>
> > > > context, Put put, WALEdit edit,
> > > >                        Durability durability) throws IOException {
> > > >         logger.info("==== Coprocessor shouldComplete :
> > > > "+context.shouldComplete()+"====");
> > > >         context.bypass();
> > > >
> > > >         Put myPut = new Put(new RowKey(1).toBytes());
> > > >
> > > >         //this call will caused an dead loop
> > > >         context.getEnvironment().getRegion().put(put);
> > > >
> > > >     }
> > > >
> > > > Thanks anyway
> > > >
> > >
> >
>

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