Increasing number of partitions on data file solved the problem.
On 6 June 2014 18:46, Oleg Proudnikov <oleg.proudni...@gmail.com> wrote: > Additional observation - the map and mapValues are pipelined and executed > - as expected - in pairs. This means that there is a simple sequence of > steps - first read from Cassandra and then processing for each value of K. > This is the exact behaviour of a normal Java loop with these two steps > inside. I understand that this eliminates batch loading first and pile up > of massive text arrays. > > Also the keys are relatively evenly distributed across Executors. > > The question is - why is this still so slow? I would appreciate any > suggestions on where to focus my search. > > Thank you, > Oleg > > > > On 6 June 2014 16:24, Oleg Proudnikov <oleg.proudni...@gmail.com> wrote: > >> Hi All, >> >> I am passing Java static methods into RDD transformations map and >> mapValues. The first map is from a simple string K into a (K,V) where V is >> a Java ArrayList of large text strings, 50K each, read from Cassandra. >> MapValues does processing of these text blocks into very small ArrayLists. >> >> The code runs quite slow compared to running it in parallel on the same >> servers from plain Java. >> >> I gave the same heap to Executors and Java. Does java run slower under >> Spark or do I suffer from excess heap pressure or am I missing something? >> >> Thank you for any insight, >> Oleg >> >> > > > -- > Kind regards, > > Oleg > > -- Kind regards, Oleg
