Can you provide details of the mutation statements you are running ? The Stack Overflow posts don't seem to include them.
Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 27/06/2013, at 5:58 AM, Theo Hultberg <t...@iconara.net> wrote: > do I understand it correctly if I think that collection modifications are > done by reading the collection, writing a range tombstone that would cover > the collection and then re-writing the whole collection again? or is it just > the modified parts of the collection that are covered by the range > tombstones, but you still get massive amounts of them and its just their > number that is the problem. > > would this explain the slowdown of writes too? I guess it would if cassandra > needed to read the collection before it wrote the new values, otherwise I > don't understand how this affects writes, but that only says how much I know > about how this works. > > T# > > > On Wed, Jun 26, 2013 at 10:48 AM, Fabien Rousseau <fab...@yakaz.com> wrote: > Hi, > > I'm pretty sure that it's related to this ticket : > https://issues.apache.org/jira/browse/CASSANDRA-5677 > > I'd be happy if someone tests this patch. > It should apply easily on 1.2.5 & 1.2.6 > > After applying the patch, by default, the current implementation is still > used, but modify your cassandra.yaml to add the following one : > interval_tree_provider: IntervalTreeAvlProvider > > (Note that implementations should be interchangeable, because they share the > same serializers and deserializers) > > Also, please note that this patch has not been reviewed nor intensively > tested... So, it may not be "production ready" > > Fabien > > > > > > > > 2013/6/26 Theo Hultberg <t...@iconara.net> > Hi, > > I've seen a couple of people on Stack Overflow having problems with > performance when they have maps that they continuously update, and in > hindsight I think I might have run into the same problem myself (but I didn't > suspect it as the reason and designed differently and by accident didn't use > maps anymore). > > Is there any reason that maps (or lists or sets) in particular would become a > performance issue when they're heavily modified? As I've understood them > they're not special, and shouldn't be any different performance wise than > overwriting regular columns. Is there something different going on that I'm > missing? > > Here are the Stack Overflow questions: > > http://stackoverflow.com/questions/17282837/cassandra-insert-perfomance-issue-into-a-table-with-a-map-type/17290981 > > http://stackoverflow.com/questions/17082963/bad-performance-when-writing-log-data-to-cassandra-with-timeuuid-as-a-column-nam/17123236 > > yours, > Theo > > > > -- > Fabien Rousseau > > > www.yakaz.com >
