On Thu, Feb 3, 2011 at 10:39 PM, Yang <teddyyyy...@gmail.com> wrote: > the pdf at the design doc > > https://issues.apache.org/jira/secure/attachment/12459754/Partitionedcountersdesigndoc.pdf > > does say so: > page 2 "- strongly consistent read: requires consistency level ALL. > (QUORUM is insufficient.) > " > > but the wiki http://wiki.apache.org/cassandra/Counters > gave a code example: > > rv = client.get_counter('key1', ColumnPath(column_family='Counter1', > column='c1'), ConsistencyLevel.ONE) > > > is one of them wrong? >
Three things: First, the design doc is talking of strongly consistent reads, the wiki gives a simple exemple of a read (it's even followed with a warning) so there is no actual contradiction here. Second, and more to the point, the design docs are slightly outdated, on this point at least. There is now support for QUORUM (or ALL) writes (since https://issues.apache.org/jira/browse/CASSANDRA-1944), so you have the usual consistency guarantee (i.e, you get strong consistency with QUORUM (resp. ONE) read provided you wrote at QUORUM (resp. ALL)). Third, it is good to recall that counters are not considered stable yet (that includes the documentations). -- Sylvain > Thanks > Yang >
