zznate / hector-examples Goto Github PK

Hi am new to cassandra 0.7. could u able to clear my doubt???

This is my code for read a single row

public class Read1Column
{
private static StringSerializer stringSerializer = StringSerializer.get();
private static DoubleSerializer doubtSerializer = DoubleSerializer.get();
public static void main(String[] args) throws Exception {

          String keyspaceName = "User";
          String columnFamilyName ="User_Details";
          String serverAddress = "localhost:9160";
          //String username="stu1";
          String Uid="0001";
          // String FirstName="ss";
         // String LastName="kk";
         // String EMail="sksk";
         String password="ssss";      
    // Create a cluster
          Cluster cluster = HFactory.getOrCreateCluster("TestCluster", serverAddress);            
          Keyspace keyspaceOperator = HFactory.createKeyspace(keyspaceName, cluster);


            try{

                Iterator<SuperRow<String, String, String, Double>> rowIter =
                    HFactory.createRangeSuperSlicesQuery(keyspaceOperator,
                            stringSerializer, stringSerializer, stringSerializer,
                            doubtSerializer)
                                        .setColumnFamily(columnFamilyName)
                                        .setKeys(Uid,password)
                                        .setRange(Uid, password, false, 40)
                                        .execute()
                                        .get()
                                        .iterator();

                    while (rowIter.hasNext()) {

                                    SuperRow<String, String, String, Double> row =
                    rowIter.next();

                                    List<HSuperColumn<String, String, Double>> scList =
                    row.getSuperSlice().getSuperColumns();

                                    for (int i=0; i<scList.size(); i++) {
                                             HSuperColumn<String, String, Double> sc =
                    scList.get(i);
                                            // Double val = sc.get(2).getValue(); 
                            // gets the value of column 2 within the supercolumn
                                             System.out.println(sc.get(2).getValue());

                                    }
                    }


            } catch (HectorException e) {
                e.printStackTrace();
            }
          //  client.getConnectionManager().shutdown();
        }

}

its show the error:

log4j:WARN No appenders could be found for logger (me.prettyprint.cassandra.connection.CassandraHostRetryService).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.NullPointerException: Null not allowed, number 1
at me.prettyprint.cassandra.utils.Assert.noneNull(Assert.java:25)
at me.prettyprint.cassandra.model.HSuperColumnImpl.(HSuperColumnImpl.java:58)
at me.prettyprint.cassandra.model.SuperSliceImpl.(SuperSliceImpl.java:35)
at me.prettyprint.cassandra.model.SuperRowImpl.(SuperRowImpl.java:34)
at me.prettyprint.cassandra.model.SuperRowsImpl.(SuperRowsImpl.java:35)
at me.prettyprint.cassandra.model.OrderedSuperRowsImpl.(OrderedSuperRowsImpl.java:28)
at me.prettyprint.cassandra.model.thrift.ThriftRangeSuperSlicesQuery$1.doInKeyspace(ThriftRangeSuperSlicesQuery.java:73)
at me.prettyprint.cassandra.model.thrift.ThriftRangeSuperSlicesQuery$1.doInKeyspace(ThriftRangeSuperSlicesQuery.java:67)
at me.prettyprint.cassandra.model.KeyspaceOperationCallback.doInKeyspaceAndMeasure(KeyspaceOperationCallback.java:20)
at me.prettyprint.cassandra.model.ExecutingKeyspace.doExecute(ExecutingKeyspace.java:65)
at me.prettyprint.cassandra.model.thrift.ThriftRangeSuperSlicesQuery.execute(ThriftRangeSuperSlicesQuery.java:66)
at Read1Column.main(Read1Column.java:40)

Hi,

How to paginate back from a 'n' the row key using RangeSlicesQuery ?

The data is based on RP and the reverse option on the setRange function seems to be applicable only for the columns not on the rows. (http://tinyurl.com/73tncn3)

Could you please provide your comments on this ?

Thanks,
Sribalaji

After running SchemaManipulation this is the output from cassandra-cli (show keyspaces)

Keyspace: DynamicKeyspace:
Replication Strategy: org.apache.cassandra.locator.SimpleStrategy
Durable Writes: true
Options: [replication_factor:1]
Column Families:
ColumnFamily: DynamicCf
Key Validation Class: org.apache.cassandra.db.marshal.BytesType
Default column value validator: org.apache.cassandra.db.marshal.BytesType
Columns sorted by: org.apache.cassandra.db.marshal.BytesType
Row cache size / save period in seconds: 0.0/0
Key cache size / save period in seconds: 0.0/0
Memtable thresholds: 0.26718749999999997/1440/57 (millions of ops/minutes/MB)
GC grace seconds: 0
Compaction min/max thresholds: 4/32
Read repair chance: 0.0
Replicate on write: false
Built indexes: []
Column Metadata:
Column Name: birthdate (626972746864617465)
Validation Class: org.apache.cassandra.db.marshal.LongType
ColumnFamily: SuperCf (Super)
Key Validation Class: org.apache.cassandra.db.marshal.BytesType
Default column value validator: org.apache.cassandra.db.marshal.BytesType
Columns sorted by: org.apache.cassandra.db.marshal.BytesType/org.apache.cassandra.db.marshal.BytesType
Row cache size / save period in seconds: 0.0/0
Key cache size / save period in seconds: 0.0/0
Memtable thresholds: 0.26718749999999997/1440/57 (millions of ops/minutes/MB)
GC grace seconds: 0
Compaction min/max thresholds: 4/32
Read repair chance: 0.0
Replicate on write: false
Built indexes: []

Compared with the Keyspace created by the Riptano documentation example

Keyspace: demo:
Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy
Durable Writes: true
Options: [datacenter1:1]
Column Families:
ColumnFamily: users
Key Validation Class: org.apache.cassandra.db.marshal.BytesType
Default column value validator: org.apache.cassandra.db.marshal.BytesType
Columns sorted by: org.apache.cassandra.db.marshal.UTF8Type
Row cache size / save period in seconds: 0.0/0
Key cache size / save period in seconds: 200000.0/14400
Memtable thresholds: 0.5484375/1440/117 (millions of ops/minutes/MB)
GC grace seconds: 864000
Compaction min/max thresholds: 4/32
Read repair chance: 1.0
Replicate on write: true
Built indexes: [users.users_birth_date_idx]
Column Metadata:
Column Name: birth_date
Validation Class: org.apache.cassandra.db.marshal.LongType
Index Name: users_birth_date_idx
Index Type: KEYS
Column Name: full_name
Validation Class: org.apache.cassandra.db.marshal.UTF8Type
Keyspace: system: