phoenix-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From James Taylor <>
Subject Re: row qualifier issue
Date Tue, 16 Sep 2014 16:21:51 GMT
Hi Abe,
You'll get best performance if you put the empty key value in the same
column family as your other column qualifiers (the ones you most
frequently filter on in your where clause). The column qualifier
should be named _0 and the value should be an empty byte array.

FYI, if you have an HBase table, but no Phoenix table yet, you can
issue a CREATE TABLE call using the HBase table name and Phoenix will
automatically add this empty key value for you.


On Tue, Sep 16, 2014 at 8:35 AM, Abe Weinograd <> wrote:
> Hello,
> I am trying to figure out an issue which I think is based on how we are
> loading data into our tables.
> We are loading data via a Map Reduce process into HFiles.  We haven't been
> adding anything for the qualifier column _0 and our performance has
> suffered.  Thanks to a quick look from a colleague, we noticed that it
> wasn't there. I am trying to figure out the best way to do this, but what
> should we actually put in the value for the qualifier?  Looking at the
> Phoenix code base it looks like the value should be Bytes.toBytes(_0).  If
> this changes will we have issues going forward?  Does it matter what the
> value is?
> Also, would we get better performance having the row qualifier in a
> different column family than all of our other columns for performance
> reasons?
> I would think that the _0 would be first int he column list, but when i do a
> scan in the HBase shell it comes up last.  Is that right?  Our columns don't
> start with anything that would make this appear this way.
> Thanks in advance for your help.  Is there somewhere i can read up on
> anything I may be missing here?
> Thanks,
> Abe

View raw message