Thanks! Robert Sicoie
On Thu, Sep 29, 2016 at 12:49 PM, Alexander Dejanovski < a...@thelastpickle.com> wrote: > Hi Robert, > > Materialized Views are regular C* tables underneath, so based on their PK > they can generate big partitions. > It is often advised to keep partition size under 100MB because larger > partitions are hard to read and compact. They usually put pressure on the > heap and lead to long GC pauses + laggy compactions. > You could possibly OOM while trying to fully read a partition that is way > too big for your heap. > > It is indeed a schema problem and you most likely have to bucket your MV > in order to split those partitions into smaller chunks. In the case of MV, > you possibly need to add a bucketing field to the table it relies on (if > you don't have one already), and add it to the MV partition key. > > You should try to use cassandra-stress to test your bucket sizes : > https://docs.datastax.com/en/cassandra/3.x/cassandra/ > tools/toolsCStress.html > In your schema definition you can now specify the creation of a MV. > > Cheers, > > > On Wed, Sep 28, 2016 at 7:35 PM Robert Sicoie <robert.sic...@gmail.com> > wrote: > >> Hi guys, >> >> I run a cluster with 5 nodes, cassandra version 3.0.5. >> >> I get this warning: >> 2016-09-28 17:22:18,480 BigTableWriter.java:171 - Writing large >> partition... >> >> for some materialized view. Some have values over 500MB. How this affects >> performance? What can/should be done? I suppose is a problem in the schema >> design. >> >> Thanks, >> Robert Sicoie >> > -- > ----------------- > Alexander Dejanovski > France > @alexanderdeja > > Consultant > Apache Cassandra Consulting > http://www.thelastpickle.com >
