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From Jeremy Hanna <jeremy.hanna1...@gmail.com>
Subject Re: cassandra 0.8.7 + hector 0.8.3: All Quorum reads result in writes?
Date Wed, 11 Apr 2012 17:04:49 GMT
I backported this to 0.8.4 and it didn't fix the problem we were seeing (as I outlined in my
parallel post) but if it fixes it for you, then beautiful.  Just wanted to let you know our
experience with similar symptoms.

On Apr 11, 2012, at 11:56 AM, Thibaut Britz wrote:

> Fixed in  https://issues.apache.org/jira/browse/CASSANDRA-3843 
> 
> 
> 
> On Wed, Apr 11, 2012 at 5:58 PM, Thibaut Britz <thibaut.britz@trendiction.com>
wrote:
> We have read repair disabled (0.0).
> 
> Even if this would be the case, this also doesn't explain why the writes are executed
again and again when going over the same range again and again.
> 
> The keyspace is new, it doesn't contain any thumbstones and only 10000 keys.
> 
> 
> 
> On Wed, Apr 11, 2012 at 5:52 PM, R. Verlangen <robin@us2.nl> wrote:
> Are you sure this isn't read-repair?  http://wiki.apache.org/cassandra/ReadRepair 
> 
> 
> 2012/4/11 Thibaut Britz <thibaut.britz@trendiction.com>
> Also executing the same multiget rangeslice query over the same range again will trigger
the same writes again and again.
> 
> On Wed, Apr 11, 2012 at 5:41 PM, Thibaut Britz <thibaut.britz@trendiction.com>
wrote:
> Hi,
> 
> I just diagnosted this strange behavior:
> 
> When I fetch a rangeslice through hector and set the consistency level to quorum, according
to cfstats (and also to the output files on the hd), cassandra seems to execute a write request
for each read I execute. The write count in cfstats is increased when I execute the rangeslice
function over the same range again and again (without saving anything at all).
> 
> If I set the consitency level to ONE, no writes are executed.
> 
> How can I disable this? Why are the records rewritten each time, even though I don't
want them to be rewritten?
> 
> Thanks,
> Thibaut.
> 
> 
> Code:
>                                 Keyspace ks = getConnection(cluster, consistencylevel);
> 
> 				RangeSlicesQuery<String, String, V> rangeSlicesQuery = HFactory.createRangeSlicesQuery(ks,
StringSerializer.get(), StringSerializer.get(), s);
> 
> 				rangeSlicesQuery.setColumnFamily(columnFamily);
> 				rangeSlicesQuery.setColumnNames(column);
> 
> 				rangeSlicesQuery.setKeys(start, end);
> 				rangeSlicesQuery.setRowCount(maxrows);
> 
> 				QueryResult<OrderedRows<String, String, V>> result = rangeSlicesQuery.execute();
> 				return result.get();
> 
> 
> 
> 
> 
> 
> 
> -- 
> With kind regards,
> 
> Robin Verlangen
> www.robinverlangen.nl
> 
> 
> 


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