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 <ty...@datastax.com> wrote: > > On Mon, Aug 29, 2011 at 4:56 PM, Peter Schuller > <peter.schul...@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 > >
