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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: can't write with consistency level of one after some nodes fail
Date Thu, 29 Oct 2009 21:39:59 GMT
can you create a ticket for this?

On Thu, Oct 29, 2009 at 3:39 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
> I've seen that bug too.  I think we introduced a regression with CASSANDRA-492.
>
> On Thu, Oct 29, 2009 at 3:37 PM, Edmond Lau <edmond@ooyala.com> wrote:
>> I've updated to trunk, and I'm still hitting the same issue but it's
>> manifesting itself differently.  Again, I'm running with a freshly
>> started 3-node cluster with a replication factor of 2.  I then take
>> down two nodes.
>>
>> If I write with a consistency level of ONE on any key, I get an
>> InvalidRequestException:
>>
>> ERROR [pool-1-thread-45] 2009-10-29 21:27:10,120 StorageProxy.java
>> (line 183) error writing key 1
>> InvalidRequestException(why:Cannot block for less than one replica)
>>        at org.apache.cassandra.service.QuorumResponseHandler.<init>(QuorumResponseHandler.java:52)
>>        at org.apache.cassandra.locator.AbstractReplicationStrategy.getResponseHandler(AbstractReplicationStrategy.java:64)
>>        at org.apache.cassandra.service.StorageService.getResponseHandler(StorageService.java:869)
>>        at org.apache.cassandra.service.StorageProxy.insertBlocking(StorageProxy.java:162)
>>        at org.apache.cassandra.service.CassandraServer.doInsert(CassandraServer.java:473)
>>        at org.apache.cassandra.service.CassandraServer.insert(CassandraServer.java:424)
>>        at org.apache.cassandra.service.Cassandra$Processor$insert.process(Cassandra.java:819)
>>        at org.apache.cassandra.service.Cassandra$Processor.process(Cassandra.java:624)
>>        at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:253)
>>        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
>>        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
>>        at java.lang.Thread.run(Thread.java:619)
>>
>> Oddly, a write with a consistency level of QUORUM succeeds for certain
>> keys (but fails with others) even though I only have one live node.
>>
>> Edmond
>>
>> On Thu, Oct 29, 2009 at 1:38 PM, Edmond Lau <edmond@ooyala.com> wrote:
>>>
>>> On Thu, Oct 29, 2009 at 1:20 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>>>
>>>> On Thu, Oct 29, 2009 at 1:18 PM, Edmond Lau <edmond@ooyala.com> wrote:
>>>> > I have a freshly started 3-node cluster with a replication factor of
>>>> > 2.  If I take down two nodes, I can no longer do any writes, even with
>>>> > a consistency level of one.  I tried on a variety of keys to ensure
>>>> > that I'd get at least one where the live node was responsible for one
>>>> > of the replicas.  I have not yet tried on trunk.  On cassandra 0.4.1,
>>>> > I get an UnavailableException.
>>>>
>>>> This sounds like the bug we fixed in CASSANDRA-496 on trunk.
>>>
>>> Excellent - thanks.  Time to start using trunk.
>>>
>>>>
>>>> > Along the same lines, how does Cassandra handle network partitioning
>>>> > where 2 writes for the same keys hit 2 different partitions, neither
>>>> > of which are able to form a quorum?  Dynamo maintained version vectors
>>>> > and put the burden on the client to resolve conflicts, but there's no
>>>> > similar interface in the thrift api.
>>>>
>>>> If you use QUORUM or ALL consistency, neither write will succeed.  If
>>>> you use ONE, both will, and the one with the higher timestamp will
>>>> "win" when the partition heals.
>>>
>>> Got it.
>>>
>>>>
>>>> -Jonathan
>>>
>>> Edmond
>>
>

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