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From Sreeram <sreera...@gmail.com>
Subject Re: Question in WALEdit
Date Wed, 22 Mar 2017 23:45:16 GMT
I am sorry for typo. For the second question I meant postWALWrite in
WALObserver.

default void postWALWrite
<https://hbase.apache.org/devapidocs/src-html/org/apache/hadoop/hbase/coprocessor/WALObserver.html#line.86>
(ObserverContext
<https://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/coprocessor/ObserverContext.html><?
extends WALCoprocessorEnvironment
<https://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/coprocessor/WALCoprocessorEnvironment.html>>
ctx,
HRegionInfo
<https://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/HRegionInfo.html>
info,
WALKey
<https://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/wal/WALKey.html>
logKey,
WALEdit
<https://hbase.apache.org/devapidocs/org/apache/hadoop/hbase/regionserver/wal/WALEdit.html>
logEdit)
throws IOException
<http://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true>

Thanks

On 23 Mar 2017 02:37, "Ted Yu" <yuzhihong@gmail.com> wrote:

> Sreeram:
> For #2, did you mean this method ?
>
>   default void postWALRestore(final ObserverContext<? extends
> RegionCoprocessorEnvironment> ctx,
>
>       HRegionInfo info, WALKey logKey, WALEdit logEdit) throws IOException
> {}
>
> On Wed, Mar 22, 2017 at 12:56 PM, Vladimir Rodionov <
> vladrodionov@gmail.com>
> wrote:
>
> > a) HBase does not support transaction - it only guarantees that single
> > mutation to a row-key is atomic. WALEdit can contains cells (mutations)
> > from different rows (for example when you do butchMutatate all operations
> > go to the same WALEdit afaik)
> > b) I coud not find postWALEdit()  in RegionObserver API. What coprocessor
> > hook did you mean exactly?
> >
> > -Vlad
> >
> > On Wed, Mar 22, 2017 at 5:19 AM, Sreeram <sreeram.v@gmail.com> wrote:
> >
> > > Hi,
> > >
> > >  I have below questions on WALEdit. Looking forward to answer from the
> > > community.
> > >
> > >  a) I understand that all Cells in a given WALEdit form part of a
> single
> > > transaction. Since HBase atomicity is at row level, this implies all
> > Cells
> > > in a given WALEdit have the same row key. is this understanding is
> > correct
> > >
> > >
> > >
> > >  b) With MultiWAL, does log sequence monotonically increase based on
> > > transaction time stamp ?  Specifically, suppose there two transactions
> > for
> > > two different tables for a single region server at times t0 and t1 (t0
> <
> > > t1). In the presence of MultiWAL, will the postWALEdit() coprocessor
> > event
> > > for transaction 0 be triggered before than transaction 1?
> > >
> > >
> > >
> > > Thanks,
> > >
> > > Sreeram
> > >
> > > PS: I use HBase version 1.2.0
> > >
> >
>

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