Does enabling compression include prefix compression (HBASE-4218), or is there a separate switch for that?
--Tom On Mon, Jan 27, 2014 at 3:48 PM, Ted Yu <[email protected]> wrote: > To make better use of block cache, see: > > HBASE-4218 Data Block Encoding of KeyValues (aka delta encoding / prefix > compression) > > which is in 0.94 and above > > To reduce size of HFiles, please see: > http://hbase.apache.org/book.html#compression > > > On Mon, Jan 27, 2014 at 2:40 PM, Nick Xie <[email protected]> > wrote: > > > Tom, > > > > Yes, you are right. According to this analysis ( > > > > > http://prafull-blog.blogspot.in/2012/06/how-to-calculate-record-size-of-hbase.html > > ) > > if it is right, then the overhead is quite big if the cell value > > occupies > > a small portion. > > > > In the analysis in that link, the overhead is actually 10x!!!!(the real > > values only takes 12B and it costs 123B in HBase to store them...) Is > that > > real???? > > > > In this case, should we do some combination to reduce the overhead? > > > > Thanks, > > > > Nick > > > > > > > > > > On Mon, Jan 27, 2014 at 2:33 PM, Tom Brown <[email protected]> wrote: > > > > > I believe each cell stores its own copy of the entire row key, column > > > qualifier, and timestamp. Could that account for the increase in size? > > > > > > --Tom > > > > > > > > > On Mon, Jan 27, 2014 at 3:12 PM, Nick Xie <[email protected]> > > > wrote: > > > > > > > I'm importing a set of data into HBase. The CSV file contains 82 > > entries > > > > per line. Starting with 8 byte ID, followed by 16 byte date and the > > rest > > > > are 80 numbers with 4 bytes each. > > > > > > > > The current HBase schema is: ID as row key, date as a 'date' family > > with > > > > 'value' qualifier, the rest is in another family called 'readings' > with > > > > 'P0', 'P1', 'P2', ... through 'P79' as qualifiers. > > > > > > > > I'm testing this on a single node cluster with HBase running in > pseudo > > > > distributed mode (no replication, no compression for HBase)...After > > > > importing a CSV file with 150MB of size in HDFS(no replication), I > > > checked > > > > the the table size, and it shows ~900MB which is 6x times larger than > > it > > > is > > > > in HDFS.... > > > > > > > > Why there is so large overhead on this? Am I doing anything wrong > here? > > > > > > > > Thanks, > > > > > > > > Nick > > > > > > > > > >
