incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jiang Chen <jia...@gmail.com>
Subject Re: Updates lost
Date Tue, 30 Aug 2011 13:42:09 GMT
The problem still happens with very high probability even when it
pauses for 5 milliseconds at every loop. If Pycassa uses microseconds
it can't be the cause. Also I have the same problem with a Java client
using Pelops.

On Tue, Aug 30, 2011 at 12:14 AM, Tyler Hobbs <tyler@datastax.com> wrote:
>
> On Mon, Aug 29, 2011 at 4:56 PM, Peter Schuller
> <peter.schuller@infidyne.com> wrote:
>>
>> > If the client sleeps for a few ms at each loop, the success rate
>> > increases. At 15 ms, the script always succeeds so far. Interestingly,
>> > the problem seems to be sensitive to alphabetical order. Updating the
>> > value from 'aaa' to 'bbb' never has problem. No pause needed.
>>
>> Is it possible the version of pycassa you're using does not guarantee
>> that successive queries use non-identical and monotonically increasing
>> timestamps?
>
> By default, pycassa uses microsecond-precision timestamps.
> ColumnFamily.insert() returns the timestamp used for the insert, so you
> could always check that it was different.  However, I doubt that you're
> getting more than one insert per microsecond, unless you have VM issues with
> the system clock.
>
> --
> Tyler Hobbs
> Software Engineer, DataStax
> Maintainer of the pycassa Cassandra Python client library
>
>

Mime
View raw message