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 > >
