incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <aa...@thelastpickle.com>
Subject Re: Unable to prefix in astyanax read query
Date Thu, 04 Apr 2013 00:35:36 GMT
>> I have created this column family using CQL and defined the primary key
>> as 
What was the create table statement ? 

>> BadRequestException: [host=localhost(127.0.0.1):9160, latency=6(6),
>> attempts=1]InvalidRequestException(why:Not enough bytes to read value of
>> component 0)
Unless the CQL 3 create table statement specifies USE COMPACT_STORAGE it will use composites
in the row keys and Astyanax may not be expected this. 

Unless astyanax specifically says it can write to CQL 3 tables it's best to only access them
using CQL 3. 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 2/04/2013, at 6:07 PM, "Hiller, Dean" <Dean.Hiller@nrel.gov> wrote:

> We ran into some similar errors in playorm development.  Basically, you
> defined a composite probably but are not correctly using that composite.
> I am not sure about queries though as we had the issue when saving data
> (ie. Using deviceID+deviceName did not work and we had to create an full
> blown composite object).  I think you need to read up on how astyanax
> works with compositesŠ..I am not sure this is a cassandra question
> reallyŠ.more of an astyanax one.
> 
> Dean
> 
> On 4/1/13 11:48 PM, "Apurva Jalit" <apurva.jalit@gmail.com> wrote:
> 
>> I have a scheme as follows:
>> 
>> TimeStamp
>> Device ID
>> Device Name
>> Device Owner
>> Device location
>> 
>> I have created this column family using CQL and defined the primary key
>> as 
>> (TimeStamp,Device ID, Device Name). Through a serializable object that
>> has 
>> fields for DeviceID, name and a field name (which stores either Device
>> Owner or 
>> Device Location). I have inserted some records using Astyanax.
>> 
>> As per my understanding, the columns for a row are created by combining
>> Device 
>> ID, Device Name and field name as column name and the value to be the
>> value for 
>> that particular field. Thus for a particular timestamp and device, the
>> column 
>> names would be in the pattern (Device ID:Device Name: ...).
>> 
>> So I believe we can use these 2 fields as prefix to obtain all the
>> entries for a 
>> particular time-device combination.
>> 
>> I am using the following query to obtain the results:
>> 
>> RowSliceQuery<String, ApBaseData> query = adu.keyspace
>> .prepareQuery(columnFamily)
>> .getKeySlice(timeStamp)
>> .withColumnRange(new RangeBuilder()
>>  .setStart(deviceID+deviceName+"_\u00000")
>>  .setEnd(deviceID+deviceName+"_\uffff")
>>  .setLimit(batch_size)
>>  .build());
>> 
>> But on executing the above query I get the following Exception:
>> 
>> BadRequestException: [host=localhost(127.0.0.1):9160, latency=6(6),
>> attempts=1]InvalidRequestException(why:Not enough bytes to read value of
>> component 0)
>> 
>> Can any one help to understand where am I going wrong?
>> 
>> 
> 


Mime
View raw message