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From Ted Yu <yuzhih...@gmail.com>
Subject Re: hbase doubts
Date Mon, 17 Aug 2015 16:25:22 GMT
How many fields such as F1 are you considering for embedding in row key ?

Suggested reading:
http://hbase.apache.org/book.html#rowkey.design
http://hbase.apache.org/book.html#client.filter.kvm (see ColumnPrefixFilter)

Cheers

On Mon, Aug 17, 2015 at 8:13 AM, Shushant Arora <shushantarora09@gmail.com>
wrote:

> 1.so size limit is per cell's identifier + value ?
>
> What is more optimise - to have field in key or in column family's column ?
> If pattern is like every row has that field.
>
> Say I have a field F1 in all rows so
> Situtatio -1
> key1#F1(as composite key)  - and rest fields in column
>
> Situation-2
> key1 as key and F1 part of column family.
>
>
> This is the main reason I  asked the key size limit.
> If I asked for no of rows where F1 is = 'someval' will it be faster in
> situation-1 than in situation-2. Since in 1 it can return the result just
> by traversing keys no need to read columns?
>
>
> On Mon, Aug 17, 2015 at 8:27 PM, Ted Yu <yuzhihong@gmail.com> wrote:
>
> > For #1, it is the limit on a single keyvalue, not row, not key.
> >
> > For #2, please see the following:
> >
> > http://hbase.apache.org/book.html#store.memstore
> > http://hbase.apache.org/book.html#regionserver_splitting_implementation
> >
> > Cheers
> >
> > On Mon, Aug 17, 2015 at 7:36 AM, Shushant Arora <
> shushantarora09@gmail.com
> > >
> > wrote:
> >
> > > 1.Is hbase.client.keyvalue.maxsize  is max size of row or key only ? Is
> > > there any limit on key size only ?
> > > 2.Access pattern is mostly on key based only- Is memstores and regions
> > on a
> > > regionserver are per table basis? Is it if I have multiple tables it
> will
> > > have multiple memstores instead of few if it would have been one large
> > > table ?
> > >
> > >
> > > On Mon, Aug 17, 2015 at 7:29 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> > >
> > > > For #1, take a look at the following in hbase-default.xml :
> > > >
> > > >     <name>hbase.client.keyvalue.maxsize</name>
> > > >     <value>10485760</value>
> > > >
> > > > For #2, it would be easier to answer if you can outline access
> patterns
> > > in
> > > > your app.
> > > >
> > > > For #3, adjustment according to current region boundaries is done
> > client
> > > > side. Take a look at the javadoc for LoadQueueItem
> > > > in LoadIncrementalHFiles.java
> > > >
> > > > Cheers
> > > >
> > > > On Mon, Aug 17, 2015 at 6:45 AM, Shushant Arora <
> > > shushantarora09@gmail.com
> > > > >
> > > > wrote:
> > > >
> > > > > 1.Is there any max limit on key size of hbase table.
> > > > > 2.Is multiple small tables vs one large table which one is
> preferred.
> > > > > 3.for bulk load -when  LoadIncremantalHfile is run it again
> > > recalculates
> > > > > the region splits based on region boundary - is this division
> happens
> > > on
> > > > > client side or server side again at region server or hbase master
> and
> > > > then
> > > > > it assigns the splits which cross target region boundary to desired
> > > > > regionserver.
> > > > >
> > > >
> > >
> >
>

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