Thanks, Paul. But about the Query Executor in HBql, I just found limited info from http://www.hbql.com/statements/create-executor-pool.html And I'm not sure how does it finish a scan, I mean, how does each thread get a [startKey, endKey]? Highly appreciated if there're more docs about the details :)
And, about the operations need whole table scan, is there 1) asynchronous operations supported? 2) Map-Reduce leveraged? Best Regards Ken Yang [Yang ZhiYong] On Wed, Jan 6, 2010 at 12:58 PM, Paul Ambrose <[email protected]> wrote: > Thanks Ken. > > The laws of HBase physics still apply. If you execute a single scan > on all the rows of a table, it is likely to be expensive. HBql allows you > to easily fire off N concurrent queries (as a series of N contiguous key > ranges in HBql) > which might give better performance. You can configure a Query Executor > in HBql to have the appropriate number of threads. I know very little > about HBase > internals, so I am not sure what the expected improvement of such > concurrency might be. > > Cheers, > Paul > > > On Jan 5, 2010, at 7:24 PM, Ken Yang wrote: > > > Hi Paul, > > > > Very impressive Job! > > And I have a question, how do you handle a query which need to scan a > whole > > table? e.g. query on a Non-indexed column. > > > > Will the operation cost too much time? > > > > > > On Wed, Jan 6, 2010 at 4:49 AM, Paul Ambrose <[email protected]> wrote: > > > >> Hi, > >> > >> I have been working on an abstraction layer for HBase that I hope > >> HBase users will find helpful. > >> > >> Highlights include: > >> * A dialect of SQL for HBase (usable in the console, scripts, and code) > >> * JDBC bindings > >> * JDBC-like bindings that support annotated objects and generics > >> * Query Executors that make threaded result reading simple > >> * Simplified filter writing for server and/or client > >> * Index support > >> > >> HBql is a work in progress and I am open to feedback and suggestions. > >> I am still working on the docs, so the examples and javadocs are pretty > >> lame. > >> > >> Have a look at: http://www.hbql.com > >> > >> Cheers, > >> Paul > >> > > > > > > > > -- > > Best Regards > > Ken Yang [Yang ZhiYong] > > -- Best Regards Ken Yang [Yang ZhiYong]
