Home | About | Sematext search-lucene.com search-hadoop.com
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase >> mail # user >> default region splitting on which value?


Copy link to this message
-
Re: default region splitting on which value?
Hi, no it's not important, only the stops are.
On Sun, Apr 21, 2013 at 3:34 AM, Ted Yu <[EMAIL PROTECTED]> wrote:

> Thanks for sharing the information below.
>
> How do you plan to store time (when the bus gets to each stop) in the row ?
> Or maybe it is not of importance to you ?
>
> On Sat, Apr 20, 2013 at 2:24 PM, Pal Konyves <[EMAIL PROTECTED]>
> wrote:
>
> > I am making a paper for school about HBase, so the data I chose is not a
> > real usable example. I am familiar with GTFS that is a de facto standard
> > for storing information about public transportation schedules: when
> vehicle
> > arrives to a stop and where it goes toward.
> >
> > I chose to genrate the rows on the fly, where each row represents a
> > sequence of 'bus' stops that make a route from the first stop until the
> > last stop.
> > e.g.: [first_stop_id,last_stop_id],string_sequence_of_stops
> > where within the [...] is the rowkey.
> >
> > So long story short, I generate the data. I want to use the HBase java
> > client api to store the rows with Put. I plan to randomize it by picking
> > random first_stop_id-s, and use more threads.
> >
> > the rowkeys will still have a sequence, because the way I generate the
> rows
> > will output about 100-1000 rows starting with the same first_stop_id
> within
> > the rowkey. The total ammount of rows will be about billions, and would
> > take up about 1TB.
> >
> >
> > On Sat, Apr 20, 2013 at 10:54 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
> >
> > > The answer to your first question is yes - midkey of the key range
> would
> > > be chosen as split key.
> > >
> > > For #2, can you tell us how you plan to randomize the loading ?
> > > Bulk load normally means preparing HFiles which would be loaded
> directly
> > > into your table.
> > >
> > > Cheers
> > >
> > > On Apr 20, 2013, at 1:11 PM, Pal Konyves <[EMAIL PROTECTED]>
> wrote:
> > >
> > > > Hi Ted,
> > > > Only one family, my data is very simple key-value, although I want to
> > > make
> > > > sequential scan, so making a hash of the key is not an option.
> > > >
> > > >
> > > >
> > > > On Sat, Apr 20, 2013 at 10:07 PM, Ted Yu <[EMAIL PROTECTED]>
> wrote:
> > > >
> > > >> How many column families do you have ?
> > > >>
> > > >> For #3, per-splitting table at the row keys corresponding to peaks
> > makes
> > > >> sense.
> > > >>
> > > >> On Apr 20, 2013, at 10:52 AM, Pal Konyves <[EMAIL PROTECTED]>
> > > wrote:
> > > >>
> > > >>> Hi,
> > > >>>
> > > >>> I am just reading about region splitting. By default - as I
> > understand
> > > -
> > > >>> Hbase handles splitting the regions. I just don't know how to
> imagine
> > > on
> > > >>> which key it splits the regions.
> > > >>>
> > > >>> 1) For example when I write MD5 hash of rowkeys, they are most
> > probably
> > > >>> evenly distributed from
> > > >>> 000000... to FFFFF... right? When  Hbase starts with one region,
> all
> > > the
> > > >>> writes goes into that region, and when the HFile get's too big, it
> > just
> > > >>> gets for example the median value of the stored keys, and split the
> > > >> region
> > > >>> by this?
> > > >>>
> > > >>> 2) I want to bulk load tons of data with the HBase java client API
> > put
> > > >>> operations. I want it to perform well. My keys are numeric
> sequential
> > > >>> values (which I know from this post, I cannot load into Hbase
> > > >> sequentially,
> > > >>> because the Hbase tables are going to be sad
> > > >>
> > >
> >
> http://ikaisays.com/2011/01/25/app-engine-datastore-tip-monotonically-increasing-values-are-bad/
> > > >>> )
> > > >>> So I thought I would pre-split the table into regions, and load the
> > > data
> > > >>> randomized. This way I will get good distribution among region
> > servers
> > > in
> > > >>> terms of network IO from the beginning. Is that a good idea?
> > > >>>
> > > >>> 3) If my rowkeys are not evenly distributed in the keyspace, but
> they
> > > >> show
> > > >>> some peaks or bursts. e.g. 000-999, but most of the keys gather
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB