Thank you for the feedback and clearing the confusion. Thanks, Gayatri
On Mon, Nov 15, 2010 at 3:59 PM, Jonathan Gray <jg...@facebook.com> wrote: > > Thank you for the feedback. So to summarize, HBase is doing good for > > high > > reads, writes. Update is really writing a new version of the data. So > > updating is okay but Handling deletes is not possible in the current > > version > > of the data unless a new version of the data is written down. > > Deletes are supported (you can delete all of a row, all of a column, or > specific versions of columns). > > They are really tombstones / markers, so the data does actually still sit > on disk for some time, but HBase will never return it back to you once it is > marked as deleted. In the background and over time, HBase will eventually > evict all of the deleted data. > > > > Also, I was reading some documentation to figure out if there is a way > > to > > store and get column values in a sorted manner. > > I understand It is possible to do range queries on key (as the key is > > sorted > > and stored) but it looks like its not straight forward to do the same > > on the > > columns values. For example I have a set of column values with a name > > and a > > score and for a given key and i want to retrieve the column names for a > > given key sorted by the score. From my understanding so far, this has > > to be > > handled at the application end. Please let me know if I am missing > > something > > here. > > You're not missing something. HBase tables are sorted by row, each row is > sorted by columns, each column is sorted by versions. There is no sorting > on values. > > You would either have to read all the values and do the sorting in the > client (sometimes this makes sense but if you have 1M columns it probably > doesn't). The other way would be to create more tables. A table can be > used to create a different index on your data (the value would now be the > row key, so the table would be sorted by value, for example). > > Hope that helps. > > JG > > > > > > > > Thanks, > > Gayatri > > > > On Mon, Nov 15, 2010 at 10:29 AM, Ryan Rawson <ryano...@gmail.com> > > wrote: > > > > > That is a static snapshot of a particular version of HBase with a > > > particular version of their code (each with various flaws, mistakes, > > > etc, etc). > > > > > > At this moment, Stumbleupon uses HBase behind parts of it's website, > > > doing reads, writes, updates, and so on. Performance is quite good, > > > and we are very happy with HBase. > > > > > > -ryan > > > > > > On Sun, Nov 14, 2010 at 8:54 PM, Hari Sreekumar > > > <hsreeku...@clickable.com> wrote: > > > > Hi, > > > > I read the comparison from this pdf: > > > > http://www.brianfrankcooper.net/pubs/ycsb-v4.pdf > > > > > > > > hari > > > > > > > > > > > > On Mon, Nov 15, 2010 at 4:20 AM, Jonathan Gray <jg...@facebook.com> > > > wrote: > > > > > > > >> HBase is well-suited for a high-write workload. > > > >> > > > >> Hari, I'm not sure what would be different in a database like > > Cassandra > > > >> with respect to updates and deletes? In this regard HBase and > > Cassandra > > > are > > > >> nearly identical (updates are really just insertions of new > > versions, > > > >> deletions are actually tombstone markers... ie data is immutable > > once > > > >> written). > > > >> > > > >> JG > > > >> > > > >> > -----Original Message----- > > > >> > From: Hari Sreekumar [mailto:hsreeku...@clickable.com] > > > >> > Sent: Friday, November 12, 2010 6:21 AM > > > >> > To: user@hbase.apache.org > > > >> > Subject: Re: Newbie question > > > >> > > > > >> > Hi Gayatri, > > > >> > > > > >> > I am myself quite new to hbase but from my little > > > >> > experience > > > >> > and from whatever I have read, HBase is more suitable for > > environments > > > >> > with > > > >> > high read and write, but very few updates and no real deletions. > > It is > > > >> > more > > > >> > of a write once and forget kind of database. Cassandra or > > MongoDB > > > might > > > >> > be > > > >> > more suitable for your requirement imo. My advice would be to > > consider > > > >> > those > > > >> > as well before making any decision. > > > >> > > > > >> > thanks, > > > >> > hari > > > >> > > > > >> > On Fri, Nov 12, 2010 at 7:00 PM, Gayatri Rao > > <rgayat...@gmail.com> > > > >> > wrote: > > > >> > > > > >> > > Hi All, > > > >> > > > > > >> > > I am new to hbase. I have been reading up documentation and > > studying > > > >> > how > > > >> > > hbase suits to our requirement. > > > >> > > > > > >> > > We want to be able to store a key and corresponding values. > > However, > > > >> > while > > > >> > > reading, i want to read values in sorted order something like > > the > > > >> > topN. Its > > > >> > > a web facing environment and our requirement is write heavy > > infact > > > >> > they are > > > >> > > updates of the already existing records (about 270K updates in > > an > > > >> > hour > > > >> > > though actual data that needs to be stored in it might be much > > much > > > >> > more). > > > >> > > Deletes would be in the order of a few thousands every day. > > > >> > > > > > >> > > I wanted to find out know your opinions on how good is hbase > > for > > > this > > > >> > kind > > > >> > > of scenario. > > > >> > > > > > >> > > Thanks, > > > >> > > Gayatri > > > >> > > > > > >> > > > > > > > >
