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HBase >> mail # user >> querying questions


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Rita 2011-10-28, 11:30
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Stack 2011-10-28, 16:23
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Re: querying questions
Thanks for your reply.

I am curious, can you give me an example of having a key as a raw bytes and
do byte comparison? I am not a native java programmer so an example would
be extremely helpful in my case.

On Fri, Oct 28, 2011 at 12:23 PM, Stack <[EMAIL PROTECTED]> wrote:

> On Fri, Oct 28, 2011 at 4:30 AM, Rita <[EMAIL PROTECTED]> wrote:
> > Couple of questions:
> > What is the best delimiter for a key? Does it even matter? I read
> somewhere
> > that using a \t is optimal for a reason.
> >
>
> Do without a delimiter if you can.  Just make the row key elements of
> fixed size.
>
> It looks like though that your your key schema would require you have
> a delimiter (I'm guessing 'server' can be anything -- or can it be
> contained so all servers have same size'd name?)
>
> If you have to have a delimiter, choose one that is illegal in a
> server name or user name so you can be sure it doesn't show up in
> either ever and throw off your parse.
>
> > For these types of queries I have been using filters particularly,
> > RegexStringComparator
> > (w/start&stop) and things seem to work to an extent. I was wondering is
> this
> > the correct way to query or is there a more optimal way?
> >
>
> Regex'ing over keys will be expensive.  HBase is all bytes.  To regex,
> you need to change the bytes into a String.  Java Strings are i18n and
> multi-byte natively so it costs making them.  Can you make your key as
> raw bytes and do byte compares in your filtering?
>
> > I also couldnt find any examples using filters for timeseries data, is
> there
> > a place I should be looking at?
> >
> >
>
> I thought tsdb used filters?
>
> St.Ack
>

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Sam Seigal 2011-10-28, 22:53
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Stack 2011-10-29, 05:49
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Rita 2011-10-29, 12:36