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HBase >> mail # user >> delete rows without writing HLog may be appear in the future?

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Re: delete rows without writing HLog may be appear in the future?
I have it on my list of things to do to allow deferred WAL flush as a per operation option (right now it's a CF option).
You really do not want to do anything with the WAL off. If you use deferred flush there is still a chance that this might happen (the RS could die in the few seconds after a Delete before it is flushed to the WAL), but it should be a rare occurrance.
-- Lars

 From: Bing Jiang <[EMAIL PROTECTED]>
Sent: Wednesday, November 21, 2012 7:20 AM
Subject: Re: delete rows without writing HLog may be appear in the future?
we need to confirm that put must be safe,but deletes must be quick and
On Nov 21, 2012 11:10 PM, "Michael Segel" <[EMAIL PROTECTED]> wrote:

> Some time later?
> Time of course is relative, so I have to ask what occurred between the
> write and the delete?
> How much time? Did you have any compactions in between the write and the
> delete?
> Why are you not consistent in your use of the WAL ?
> On Nov 21, 2012, at 6:37 AM, Bing Jiang <[EMAIL PROTECTED]> wrote:
> > hi,all.
> > I want to describe a phenomenon that happens to our hbase cluster.
> > I use puts(List<Put>) to insert many records with writing hlog enable,
> > and some time later I delete all of these records with writing hlog
> disable.
> > When one week later, i scan the table, I found some records I have delete
> > reappear again.
> > It is an interesting case. In my opinion, if we delete data without
> enable
> > writing hlog, when regionserver fails, the log will replay in another
> > regionserver.
> > Can anyone tell me if I persist on deleting records without enable
> writing
> > hlog, is there a way to prevent these records from reappearing again some
> > time later?
> >
> > Cheers!
> > --
> > Bing Jiang
> > weibo: http://weibo.com/jiangbinglover
> > BLOG: http://blog.sina.com.cn/jiangbinglover
> > BLOG: http://www.binospace.com
> > National Research Center for Intelligent Computing Systems
> > Institute of Computing technology
> > Graduate University of Chinese Academy of Science