Nice review Bin Yang. HQL may/will be moved to the HrdfStore project (http://wiki.apache.org/incubator/HRdfStoreProposal) because it is not a Hbase community(BigTable clone)'s goal and i'm not a leader of Hbase, So i can't answer your question.
Instead, HRdfStore and Query Languages will show the answer. On 3/6/08, Bin YANG <[EMAIL PROTECTED]> wrote: > Dear Edward Yoon, > > What I want to know is how HBase to execute the HQL query. > > I know that the SELECT in HQL can just specify row keys in WHERE clause. > If I want to make the WHERE support column=***, I think HBase need indices. > So, I want to know how does "WHERE row keys = ***" do now. > > About the column-oriented database, I know C-Store is a example. > C-Sotre is a complete relational database, while the bigtable is not a > relational database. > Bigtable just supports to store simple relational data. So that, I > think Bigtable should have > different index models compared with column-oriented database. > > I think CAN is one of the Distributed Hash Table, maybe CHORD, PASTRY > is similar to CAN. > DHT can store data as a key find the data according to the key, but it > cannot support store data with locality. > For example, if you want to store two webpage form same site in one > node, the bigtable can assure the requirement, > but the DHT cannot assure. Using DHT, the two webpage may store in two > nodes, because the content of the two > pages are different. > > What is your opinion on how to support powerful HQL in HBase or Bigtable? > > Cheers, > Bin YANG > > On Thu, Mar 6, 2008 at 5:55 PM, edward yoon <[EMAIL PROTECTED]> wrote: > > >> I suppose that a hash function which hash row key to physical address > > is more efficient. > > > > Actually, I thought and consider about CAN (Content-Addressable > > Network) because BigTable has a immutable meta tree as a b+tree. > > I don't exactly know what do you think, but it is a revolutionary idea. > > > > If I may digress from my theme for a moment, > > For 30 years, The benefits of column-store development has been the > > subject of much/some debate. but, the availability of column-store has > > not been authenticated. > > And also, i couldn't proof an benefits of Hbase (BigTable clone) > > because there is an various alternative suggestions. But, I recently > > find a answer that they only made a BigTable for fun. > > > > > > > > On 3/6/08, Bin YANG <[EMAIL PROTECTED]> wrote: > > > Dear colleagues, > > > > > > I have a questions on HBase's index implementation. > > > > > > How does the HBase find the data according to a row key? Use a index > > > like database, or use a hash function? > > > I suppose that a hash function which hash row key to physical address > > > is more efficient. > > > > > > As we know, a big table in HBase is stored as several Small tables, > > > each table stores attributes in a column family. > > > So that, each row may be stored in several small tables. > > > Does a hash function hash row key to many physical address? Each > > > physical address correspond to a small table which contains the row > > > key? > > > > > > Does anybody have idea on how to create a index on other attribute? > > > > > > Best, > > > Bin YANG > > > > > > -- > > > Bin YANG > > > Department of Computer Science and Engineering > > > Fudan University > > > Shanghai, P. R. China > > > EMail: [EMAIL PROTECTED] > > > > > > > > > -- > > B. Regards, > > Edward yoon @ NHN, corp. > > > > > > -- > Bin YANG > Department of Computer Science and Engineering > Fudan University > Shanghai, P. R. China > EMail: [EMAIL PROTECTED] > -- B. Regards, Edward yoon @ NHN, corp.
