3 Replies Latest reply on Nov 30, 2015 9:18 AM by Ramesh Reddy

    Issue faced while using SimpleDb and Cassandra connector

    Pranav K Novice

      Hi,

       

      I noticed that while writing to a VDB using the Cassandra connector (Cassandra based source model contained within a VDB), writes were going very slow. On a single node Cassandra setup inserting a set 50k records and 3 columns took more than 25 mins. Regular writes to cassandra are supposed to very fast. Just wanted to know whether this is an expected/known fact considering the Cassandra apis being called?

      I suppose the connector executes the insert queries one by one rather than using batched approach, also the API used is the synchronous one instead of the future based async API [session.executeAsync()]

       

      SimpleDb:

      I also noticed that a 'select count(*) from table' query doesnt work with SimpleDb connector. A 'select count(column1)...' works, however.

      Following was the error which came up:

      TEIID30504 vd-sdb_1-simpledb: Inproper results returned. Expected 1 columns, but was 0

      On debugging I noticed that a conditional check for expression type seems to be missing in the method visit(DerivedColumn obj) in the class SimpleDBSQLVisitor, hence projectedColumns list remains empty.

       

      Thanks,

      Pranav