Leftouterjoin and join apis are super slow in spark. 100x slower than hadoop
Sent from my iPhone > On 14-Jul-2015, at 10:59 PM, Wush Wu <wush...@gmail.com> wrote: > > I don't understand. > > By the way, the `joinWithCassandraTable` does improve my query time > from 40 mins to 3 mins. > > > 2015-07-15 13:19 GMT+08:00 ÐΞ€ρ@Ҝ (๏̯͡๏) <deepuj...@gmail.com>: >> I have explored spark joins for last few months (you can search my posts) >> and its frustrating useless. >> >>> On Tue, Jul 14, 2015 at 9:35 PM, Wush Wu <wush...@gmail.com> wrote: >>> >>> Dear all, >>> >>> I have found a post discussing the same thing: >>> >>> https://groups.google.com/a/lists.datastax.com/forum/#!searchin/spark-connector-user/join/spark-connector-user/q3GotS-n0Wk/g-LPTteCEg0J >>> >>> The solution is using "joinWithCassandraTable" and the documentation >>> is here: >>> https://github.com/datastax/spark-cassandra-connector/blob/v1.3.0-M2/doc/2_loading.md >>> >>> Wush >>> >>> 2015-07-15 12:15 GMT+08:00 Wush Wu <wush...@gmail.com>: >>>> Dear all, >>>> >>>> I am trying to join two RDDs, named rdd1 and rdd2. >>>> >>>> rdd1 is loaded from a textfile with about 33000 records. >>>> >>>> rdd2 is loaded from a table in cassandra which has about 3 billions >>>> records. >>>> >>>> I tried the following code: >>>> >>>> ```scala >>>> >>>> val rdd1 : (String, XXX) = sc.textFile(...).map(...) >>>> import org.apache.spark.sql.cassandra.CassandraSQLContext >>>> cc.setKeyspace("xxx") >>>> val rdd2 : (String, String) = cc.sql("SELECT x, y FROM xxx").map(r => >>>> ...) >>>> >>>> val result = rdd1.leftOuterJoin(rdd2) >>>> result.take(20) >>>> >>>> ``` >>>> >>>> However, the log shows that the spark loaded 3 billions records from >>>> cassandra and only 33000 records left at the end. >>>> >>>> Is there a way to query the cassandra based on the key in rdd1? >>>> >>>> Here is some information of our system: >>>> >>>> - The spark version is 1.3.1 >>>> - The cassandra version is 2.0.14 >>>> - The key of joining is the primary key of the cassandra table. >>>> >>>> Best, >>>> Wush >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: user-unsubscr...@spark.apache.org >>> For additional commands, e-mail: user-h...@spark.apache.org >> >> >> >> -- >> Deepak >> --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@spark.apache.org For additional commands, e-mail: user-h...@spark.apache.org
