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HBase, mail # user - Reading table sequentially...


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Re: Reading table sequentially...
Something Something 2010-01-13, 05:32
Thanks for the explanation.  So as per the link you provided the list()
method would return a sorted list, correct?

About the 2nd point, I am using result.getFamilyMap() which returns
NavigableMap which extends SortedMap (as per
http://java.sun.com/javase/6/docs/api/java/util/NavigableMap.html?is-external=true),
so I guess the returned Map would be sorted by key values, so I am safe
there as well, correct?
On Tue, Jan 12, 2010 at 4:46 PM, stack <[EMAIL PROTECTED]> wrote:

> On Tue, Jan 12, 2010 at 2:01 PM, Something Something <
> [EMAIL PROTECTED]> wrote:
>
> > All the Keys returned by this code are guaranteed to be in order by the
> key
> > values, correct?
> >
>
> No.  Explicitly, the order is NOT guaranteed, for performance reasons (I
> don't see this in the javadoc.  It should be there).  If just getting
> latest
> version from a set of columns, I believe it will come across in the right
> order but not guaranteed.  To get a guaranteed sorted order, call
>
> http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Result.html#sorted()instead<http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Result.html#sorted%28%29instead>
> of the raw() method.  The sort will be done client-side.
>
>
> >
> > Also, for some other table I am retrieving all column names for a
> > particular
> > key, and those all seem to be in the correct order as well.  Is this
> always
> > guaranteed?
> >
>
>  Call sort if you need guarantee.
>
> St.Ack
>
>
>
>
>
>
>
> >
> > On Tue, Jan 12, 2010 at 11:12 AM, stack <[EMAIL PROTECTED]> wrote:
> >
> > > Setup the scanner and next it as you did previous.  Then on the Result
> > > object, do something like:
> > >
> > > for (KeyValue kv: result.raw()) {
> > >  System.out.println(Bytes.toString(kv.getRow()) + " " +
> > > Bytes.toString(kv.getValue()));
> > > }
> > >
> > > St.Ack
> > >
> > > On Tue, Jan 12, 2010 at 10:24 AM, Something Something <
> > > [EMAIL PROTECTED]> wrote:
> > >
> > > > Sorry.  That was a typo.  In any case, it seems like I am using the
> > wrong
> > > > API.
> > > >
> > > > Here's what my table contains:
> > > >
> > > >
> > > >  ABC_111                     column=info:estimate,
> > > timestamp=1263319888463,
> > > > value=179.59
> > > >  ABC_222                     column=info:estimate,
> > > timestamp=1263319888463,
> > > > value=191.50
> > > >  ABC_333                     column=info:estimate,
> > > timestamp=1263319888463,
> > > > value=180.65
> > > >  ABC_444                     column=info:estimate,
> > > timestamp=1263319888463,
> > > > value=183.63
> > > >  & so on....
> > > >
> > > >
> > > > I want to retrieve:
> > > >
> > > > ABC_111  179.59
> > > > ABC_222  191.50
> > > > ABC_333  180.65
> > > > ABC_444  183.63
> > > > & so on...
> > > >
> > > > What API should I use?  Please let me know.  Thanks for your help.
> > > >
> > > >
> > > > On Tue, Jan 12, 2010 at 9:36 AM, stack <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > See below:
> > > > >
> > > > > On Tue, Jan 12, 2010 at 9:12 AM, Something Something <
> > > > > [EMAIL PROTECTED]> wrote:
> > > > > >
> > > > > >            NavigableMap<byte[], NavigableMap<byte[],
> > > NavigableMap<Long,
> > > > > > byte[]>>> map = result.getMap();
> > > > > >
> > > > >
> > > > > Above returns a map keyed by families:
> > > > >
> > > > >
> > > >
> > >
> >
> http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Result.html#getMap%28%29
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > >            for (Map.Entry<byte[], NavigableMap<byte[],
> > > > NavigableMap<Long,
> > > > > > byte[]>>> entry : map.entrySet()) {
> > > > > >            byte[] key = entry.getKey();
> > > > > >
> > > > >
> > > > > This is family name, not key.
> > > > >
> > > > >
> > > > >
> > > > > >            *LOG.info("key = " + Bytes.toString(key));*
> > > > > >            NavigableMap<byte[], NavigableMap<Long, byte[]>> value
> > > > > > > entry.getValue();
> > > > > >
> > > > >
> >