hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From ramkrishna vasudevan <ramkrishna.s.vasude...@gmail.com>
Subject Re: Is there a way to only scan data in memstore
Date Thu, 21 Mar 2013 09:56:28 GMT
The way that Anoop has suggested will make you issue a scan command from
the client but the CP hook will tel you what are the KVs in the memstore
based on that particular scan's current read point.

I think to scan the HFiles directly are you using MapReduce?  Or you are
directly reading the HFiles knowing the HDFS path?

Currently i don think there is any way to access a Memstore directlly,
leave even the Memstore you cannot access the HRegion directly if am not
wrong.

Regards
Ram

On Thu, Mar 21, 2013 at 3:14 PM, Snake <yfwang@xingcloud.com> wrote:

> We are attempting to implement hbase as data source in drill.  We don't
> want to use hbase client to scan data(performance consideration). We
> divided the scan process into two parts, read hfile directly and read data
> in memstore from region server.
> 在 2013-3-21,下午5:31, Anoop Sam John 写道:
>
> > How you can be sure abt data will be in memstore only. What if in btw
> flush happening?   Which version in use?
> > In 94.x version (I am not sure abt the .x version no#) there is
> preStoreScannerOpen() CP hook. This impl can return a KVScanner for a store
> (In your impl the scanner can be only for Memstore?). Pls see how this hook
> is being used and how the StoreScanner is being created.
> >
> > Can you think of control this using TimeRange on Scan ?
> >
> > -Anoop-
> > ________________________________________
> > From: Snake [yfwang@xingcloud.com]
> > Sent: Thursday, March 21, 2013 2:35 PM
> > To: user@hbase.apache.org
> > Subject: Is there a way to only scan data in memstore
> >
> > Hi,
> >
> > I just want to scan data in memstore, but I saw InternalScan is private
> class.  Is there a way i can do it without change the hbase source code?
> >
> > Thanks,
> > Snake
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message