You do not want to repeat the first item of your primary key again. If you
recall, in CQL3 a primary key as defined below indicates that the row key is
the first item (key) and then the column names are composites of val1,val2.
Although I don't see why you need val2 as part of the primary key in this case.
In any event, you would do something like this (although I've never tested
passing a null value):
ssTableWriter.newRow(StringSerializer.get().toByteBuffer("20101201"));
Composite columnComposite = new Composite();
columnComposite(0,5,IntegerSerializer.get());
columnComposite(0,10,IntegerSerializer.get());
ssTableWriter.addColumn(
CompositeSerializer.get().toByteBuffer(columnComposite),
null,
System.currentTimeMillis()
);
From: Daniel Morton <[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Date: Thursday, May 30, 2013 1:06 PM
To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Subject: Bulk loading into CQL3 Composite Columns
Hi All. I am trying to bulk load some data into a CQL3 table using the
sstableloader utility and I am having some difficulty figuring out how to use
the SSTableSimpleUnsortedWriter with composite columns.
I have created this simple contrived table for testing:
create table test (key varchar, val1 int, val2 int, primary key (key, val1,
val2));
Loosely following the bulk loading example in the docs, I have constructed the
following method to create my temporary SSTables.
public static void main(String[] args) throws Exception {
final List<AbstractType<?>> compositeTypes = new ArrayList<>();
compositeTypes.add(UTF8Type.instance);
compositeTypes.add(IntegerType.instance);
compositeTypes.add(IntegerType.instance);
final CompositeType compType =
CompositeType.getInstance(compositeTypes);
SSTableSimpleUnsortedWriter ssTableWriter =
new SSTableSimpleUnsortedWriter(
new File("/tmp/cassandra_bulk/bigdata/test"),
new Murmur3Partitioner() ,
"bigdata",
"test",
compType,
null,
128);
final Builder builder =
new CompositeType.Builder(compType);
builder.add(bytes("20101201"));
builder.add(bytes(5));
builder.add(bytes(10));
ssTableWriter.newRow(bytes("20101201"));
ssTableWriter.addColumn(
builder.build(),
ByteBuffer.allocate(0),
System.currentTimeMillis()
);
ssTableWriter.close();
}
When I execute this method and load the data using sstableloader, if I do a
'SELECT * FROM test' in cqlsh, I get the results:
key | val1 | val2
----------------------------
20101201 | '20101201' | 5
And the error: Failed to decode value '20101201' (for column 'val1') as int.
The error I get makes sense, as apparently it tried to place the key value into
the val1 column. From this error, I then assumed that the key value should not
be part of the composite type when the row is added, so I removed the UTF8Type
from the composite type, and only added the two integer values through the
builder, but when I repeat the select with that data loaded, Cassandra throws
an ArrayIndexOutOfBoundsException in the ColumnGroupMap class.
Can anyone offer any advice on the correct way to insert data via the bulk
loading process into CQL3 tables with composite columns? Does the fact that I
am not inserting a value for the columns make a difference? For my particular
use case, all I care about is the values in the column names themselves (and
the associated sorting that goes with them).
Any info or help anyone could provide would be very much appreciated.
Regards,
Daniel Morton
