Cassandra json2sstable Null Pointer Exception

Question

I'm using Cassandra 0.7.4. I have been breaking my head for most of today to make a simple import with json2sstable util. I'm in Test Cluster.

I create a simple keyspace KS1. 
I create a simple CF mycf. 
I insert a row with only one column like set mycf[key1][col1]='col1value'

I export the above with sstable2json util to a file called out. But when I try the reverse (import) it always gives NPE.

C:\>json2sstable -K KS1 -c mycf C:/out C:/var/lib/cassandra/data/kS1/mycf-f-2-Data.db
java.lang.NullPointerException
        at org.apache.cassandra.db.ColumnFamily.create(ColumnFamily.java:67)
        at org.apache.cassandra.db.ColumnFamily.create(ColumnFamily.java:61)
        at org.apache.cassandra.tools.SSTableImport.importJson(SSTableImport.java:194)
        at org.apache.cassandra.tools.SSTableImport.main(SSTableImport.java:421)
ERROR: null

I looked at the source code. There is an assert where the CFMetaData is checked to be not null. This is obviously saying it is null but why?

any suggestions greatly appreciated.

Answer 1

Ok this is what I did - I couldnt delete the post so just recording what I did. I did a fresh install of Cassandra 0.7.4. I did the same steps again. This time I just changed the timestamp value of the column a little (some random increase). The NPE was gone but it gave a out of memory error. I read here if you get the OOM error you can resolve it by changing the compaction setting in cassandra.yaml. Changed that and it works now. I really dont know which of the steps fixed the problem.