Thanks Ted. I think the fix you mentioned is this one HBASE-12078 <https://issues.apache.org/jira/browse/HBASE-12078>.
Not sure when our Hadoop admin would upgrade it, ahhh.... Jianshi On Thu, Nov 13, 2014 at 11:15 PM, Ted Yu <[email protected]> wrote: > Keep in mind that Prefix Tree encoding has higher overhead in write path > compared to other data block encoding methods. > > Please use 0.98.7 which has the latest fixes for Prefix Tree encoding. > > Cheers > > On Thu, Nov 13, 2014 at 1:27 AM, Jianshi Huang <[email protected]> > wrote: > > > Thanks Ram, > > > > How about Prefix Tree based encoding then? HBASE-4676 > > <https://issues.apache.org/jira/browse/HBASE-4676> says it's also > possible > > to do suffix tries? Then it could be a nice fit for JSON String (or any > > long value where changes are small). > > > > Maybe I should just flatten JSON to columns, hmm...what's the overhead > for > > a column? > > > > Jianshi > > > > On Thu, Nov 13, 2014 at 4:49 PM, ramkrishna vasudevan < > > [email protected]> wrote: > > > > > >>So is it possible to specify FASTDIFF for rowkey/column and DIFF for > > > value > > > cell? > > > No that is not possible now. All the encoding is per KV only. > > > But what you say is definitely worth trying. > > > > > > >>So would you recommend storing JSON flattened as many columns? > > > May be yes. But I have practically not used JSON formats so I may not > be > > > the best person to comment on this. > > > > > > Regards > > > Ram > > > > > > On Thu, Nov 13, 2014 at 2:01 PM, Jianshi Huang < > [email protected]> > > > wrote: > > > > > > > Thanks Ram, > > > > > > > > So is it possible to specify FASTDIFF for rowkey/column and DIFF for > > > value > > > > cell? > > > > > > > > So would you recommend storing JSON flattened as many columns? > > > > > > > > Jianshi > > > > > > > > On Thu, Nov 13, 2014 at 2:08 PM, ramkrishna vasudevan < > > > > [email protected]> wrote: > > > > > > > > > Hi > > > > > > > > > > >> Since I'm storing > > > > > historical data (snapshot data) and changes between adjacent value > > > cells > > > > > are relatively small. > > > > > > > > > > If the values are changing even if it is smaller the FASTDIFF will > > > > rewrite > > > > > the value part. Only if there are exact matches then it would skip > > the > > > > > value part. JFYI. > > > > > > > > > > Regards > > > > > Ram > > > > > > > > > > On Thu, Nov 13, 2014 at 11:23 AM, Jianshi Huang < > > > [email protected] > > > > > > > > > > wrote: > > > > > > > > > > > I thought FASTDIFF was only for rowkey and columns, great if it > > also > > > > > works > > > > > > in value cell. > > > > > > > > > > > > And thanks for the bjson link! > > > > > > > > > > > > Jianshi > > > > > > > > > > > > On Thu, Nov 13, 2014 at 1:18 PM, Ted Yu <[email protected]> > > wrote: > > > > > > > > > > > > > There is FASTDIFF data block encoding. > > > > > > > > > > > > > > See also http://bjson.org/ > > > > > > > > > > > > > > Cheers > > > > > > > > > > > > > > On Nov 12, 2014, at 9:08 PM, Jianshi Huang < > > > [email protected]> > > > > > > > wrote: > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > I'm currently saving JSON in pure String format in the value > > cell > > > > and > > > > > > > > depends on HBase' block compression to reduce the overhead of > > > JSON. > > > > > > > > > > > > > > > > I'm wondering if there's a more space efficient way to store > > > JSON? > > > > > > > > (there're lots of 0s and 1s, JSON String actually is an OK > > > format) > > > > > > > > > > > > > > > > I want to keep the value as a Map since the schema of source > > data > > > > > might > > > > > > > > change over time. > > > > > > > > > > > > > > > > Also is there a DIFF based encoding for values? Since I'm > > storing > > > > > > > > historical data (snapshot data) and changes between adjacent > > > value > > > > > > cells > > > > > > > > are relatively small. > > > > > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > -- > > > > > > > > Jianshi Huang > > > > > > > > > > > > > > > > LinkedIn: jianshi > > > > > > > > Twitter: @jshuang > > > > > > > > Github & Blog: http://huangjs.github.com/ > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Jianshi Huang > > > > > > > > > > > > LinkedIn: jianshi > > > > > > Twitter: @jshuang > > > > > > Github & Blog: http://huangjs.github.com/ > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > Jianshi Huang > > > > > > > > LinkedIn: jianshi > > > > Twitter: @jshuang > > > > Github & Blog: http://huangjs.github.com/ > > > > > > > > > > > > > > > -- > > Jianshi Huang > > > > LinkedIn: jianshi > > Twitter: @jshuang > > Github & Blog: http://huangjs.github.com/ > > > -- Jianshi Huang LinkedIn: jianshi Twitter: @jshuang Github & Blog: http://huangjs.github.com/
