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From innowireless TaeYun Kim <taeyun....@innowireless.co.kr>
Subject RE: What is in a HBase block index entry?
Date Thu, 07 Aug 2014 05:05:16 GMT
Thank you Anoop.

Though it's a bit strange to include CF in the index, since all the block index is contained
in a HFile for a specific CF, I'm sure there would be a good reason (maybe for the performance
of the comparison).
Anyways it should be almost no issue since the length of the CF should be short(mostly one
byte).

Thanks.

-----Original Message-----
From: Anoop John [mailto:anoop.hbase@gmail.com] 
Sent: Thursday, August 07, 2014 1:40 PM
To: user@hbase.apache.org
Subject: Re: What is in a HBase block index entry?

It will be the key of the KeyValue.  Key includes rk + cf + qualifier + ts + type.

So all these part of key.  Your annswer#1 is correct (but with addition of type also)..  Hope
this make it clear for you.

-Anoop-

On Tue, Aug 5, 2014 at 9:43 AM, innowireless TaeYun Kim < taeyun.kim@innowireless.co.kr>
wrote:

> So, is it safe to assume that there is no documentation for the exact 
> content of the block index?
> I think that reading the source code should be the last resort, since 
> one cannot sure whether it is an implementation detail, or it is the 
> specification that can be relied upon.
> The information on the exact content of the block index is important, 
> since it is related in the size of the index (let alone the query
> performance) and therefore the schema design.
>
> Or, could you please simply provide the exact answer to my original 
> question(with proper reference)?
>
> Thank you.
>
> -----Original Message-----
> From: Ted Yu [mailto:yuzhihong@gmail.com]
>  Sent: Tuesday, August 05, 2014 12:59 PM
> To: user@hbase.apache.org
> Subject: Re: What is in a HBase block index entry?
>
> I suggest you read the source code of KeyValue class.
> e.g. you can start with this method:
>
>   public static long getKeyDataStructureSize(int rlength, int flength, 
> int
> qlength) {
>
> Cheers
>
>
> On Mon, Aug 4, 2014 at 8:13 PM, innowireless TaeYun Kim < 
> taeyun.kim@innowireless.co.kr> wrote:
>
> > So, your answer is 1. in my list?
> > I don’t think so since the column family information is not necessary.
> > Could you please refer a more direct information?
> >
> >
> > -----Original Message-----
> > From: Ted Yu [mailto:yuzhihong@gmail.com]
> > Sent: Tuesday, August 05, 2014 12:01 PM
> > To: user@hbase.apache.org
> > Subject: Re: What is in a HBase block index entry?
> >
> > Please see:
> > http://hbase.apache.org/book.html#keyvalue
> >
> >
> > On Mon, Aug 4, 2014 at 7:55 PM, innowireless TaeYun Kim < 
> > taeyun.kim@innowireless.co.kr> wrote:
> >
> > > Thank you for your reply.
> > >
> > > It only says 'Key'.
> > > That's what I'm confused.
> > >
> > >
> > > -----Original Message-----
> > > From: Ted Yu [mailto:yuzhihong@gmail.com]
> > > Sent: Tuesday, August 05, 2014 11:45 AM
> > > To: user@hbase.apache.org
> > > Subject: Re: What is in a HBase block index entry?
> > >
> > > Have you read this ?
> > > http://hbase.apache.org/book.html#d3593e20175
> > >
> > > Cheers
> > >
> > >
> > > On Mon, Aug 4, 2014 at 7:24 PM, innowireless TaeYun Kim < 
> > > taeyun.kim@innowireless.co.kr> wrote:
> > >
> > > > Hi,
> > > >
> > > > This is a newbie question.
> > > >
> > > >
> > > >
> > > > What is in a HBase block index entry?
> > > >
> > > >
> > > >
> > > > My guess is that it's one of these:
> > > >
> > > >
> > > >
> > > > 1.      all key components: rowkey + column family + column
> qualifier +
> > > > timestamp
> > > >
> > > > 2.      all key components except for column family (since the index
> is
> > > in
> > > > a
> > > > HFile that is a part of the storage for a column family): rowkey 
> > > > + column qualifier + timestamp
> > > >
> > > > 3.      rowkey only
> > > >
> > > >
> > > >
> > > > I've tried to find the information, But the articles only say 
> > > > that it contains a 'key'. For me as a newbie, it is confusing 
> > > > since in a KeyValue the all key components comprise the 'key', 
> > > > while a rowkey is
> > > also a 'key'.
> > > >
> > > >
> > > >
> > > > Thanks.
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>


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