https://issues.apache.org/jira/browse/CASSANDRA-2843
thanks Yang On Fri, Jul 1, 2011 at 12:09 AM, Sylvain Lebresne <sylv...@datastax.com>wrote: > I think it's an interesting solution. And we can probably avoid the two > getTopLevelColumns flavors with at bit a refactor. Let's open a ticket > however, > because this is starting to be off-topic for the user mailing list. > > -- > Sylvain > > On Fri, Jul 1, 2011 at 12:44 AM, Yang <teddyyyy...@gmail.com> wrote: > > ok, I kind of found the magic bullet , but you can only use it to shoot > your > > enemy close really close range :) > > > > for read path, the thrift API already limits the output to a list of > > columns, so it does not make sense to use maps in the internal > operations. > > plus the return CF on the read path is not going to be modified/shared by > > any other threads, so synchronization is not necessary. so > > the solution is to modify ColumnFamilyStore so that getTopLevelColumns > takes > > a returnCF param, instead of always constructing it inside with > > ColumnFamily.create(). > > so only read path behavior is changed. > > in read path, we pass in a FastColumnFamily implementation, which uses an > > ArrayList internally to store sorted columns, and do binary search to > insert > > , and merge to addAll(column). > > I tried out this, it's about 50% faster on rows with 3000 cols. > > > > Jonathan: do you think this is a viable approach? the only disadvantage > is a > > slight change to getTopLevelColumns so we have 2 flavors of this method > > Thanks > > Yang > > > > On Wed, Jun 29, 2011 at 5:51 PM, Jonathan Ellis <jbel...@gmail.com> > wrote: > >> > >> On Tue, Jun 28, 2011 at 10:06 PM, Yang <teddyyyy...@gmail.com> wrote: > >> > I'm trying to see whether there are some easy magic bullets for a > >> > drop-in > >> > replacement for concurrentSkipListMap... > >> > >> I'm highly interested if you find one. :) > >> > >> -- > >> Jonathan Ellis > >> Project Chair, Apache Cassandra > >> co-founder of DataStax, the source for professional Cassandra support > >> http://www.datastax.com > > > > >
