Re: Answering the question of Cassandra Summit 2017

[Ben Bromhead]

Thanks for explanation Patrick, I think it helps the community to hear
direct from the horses mouth.

I also wanted to thank you, your team and Datastax for being the organising
force behind the Cassandra Summit for all these years. Politics aside it
has been an awesome place for the community to meet, bond and make some
great (and sometimes hazy) memories!

In terms of the future, I'm pretty positive there will be a place and
format for the Apache Cassandra community to meet in person in the new year
and the fact that Datastax would be an enthusiastic participant is
wonderful.

<3 The Instaclustr team

On Fri, 11 Aug 2017 at 17:27 Patrick McFadin  wrote:

> Hello Cassandra Community,
>
> I know this is a hot topic so let me TL;DR for those of you looking for
> the short answer. Will there be a Cassandra Summit in 2017? DataStax will
> not be holding a Cassandra Summit in 2017, but instead multiple DataStax
> Summits in 2018.
>
> More details. Last year was pretty chaotic for the Cassandra community and
> where DataStax fit with the project. I don’t need to re-cap all the drama.
> You can go look at the dev and user lists around this time last year if you
> want to re-live it. It’s safe to say 2016 is a year I wouldn’t want to do
> again for a lot of reasons. Those of us at the Cassandra Summit 2016 knew
> it was the end of something, now the question is what’s next and what will
> it be?
>
> Having a place for people together and talk about what we as a community
> do is really important. Those of you that know me, know how much I live
> that. When we started talking summit inside DataStax, we realized it would
> be a hot button issue. When I started talking to people in the community,
> it was even more of a hot button issue. Having DataStax run the Cassandra
> Summit was going to cause a lot of heartache and would further divide the
> community with questions and accusations. It’s just much easier to hold a
> DataStax Summit so we are just out there plainly and move forward.
>
> What DataStax will be doing different.
>
> We will be moving back to a more regional format instead of the big bang
> single event in San Jose starting in 2018. Fun fact. Almost 80% of
> attendees of Cassandra Summit were from the Bay Area. That means we have
> developers and operators from a lot of other places being excluded which
> isn’t cool. We will also be inviting talks from the Cassandra Community.
> You don’t have to be a DataStax customer or partner to get on the speaking
> list.
>
> If there is some new group or company that launches a Cassandra Summit,
> DataStax will happily be a sponsor. There are some for-profit, professional
> conference companies like the Linux Foundation out there that just may and
> if so, I’ll see you there. After being involved in making the Cassandra
> Summit happen for years, I can say it’s no small effort.
>
> There it is. Fire away with your questions, comments. All I ask is keep it
> respectful because this is a community of amazing people. You have changed
> the world over these years and I know it won’t stop. You know I got a hug
> for you wherever we just happen to meet.
>
> Patrick
>
> --
Ben Bromhead
CTO | Instaclustr 
+1 650 284 9692
Managed Cassandra / Spark on AWS, Azure and Softlayer

Answering the question of Cassandra Summit 2017

[Patrick McFadin]

Hello Cassandra Community,

I know this is a hot topic so let me TL;DR for those of you looking for the
short answer. Will there be a Cassandra Summit in 2017? DataStax will not
be holding a Cassandra Summit in 2017, but instead multiple DataStax
Summits in 2018.

More details. Last year was pretty chaotic for the Cassandra community and
where DataStax fit with the project. I don’t need to re-cap all the drama.
You can go look at the dev and user lists around this time last year if you
want to re-live it. It’s safe to say 2016 is a year I wouldn’t want to do
again for a lot of reasons. Those of us at the Cassandra Summit 2016 knew
it was the end of something, now the question is what’s next and what will
it be?

Having a place for people together and talk about what we as a community do
is really important. Those of you that know me, know how much I live that.
When we started talking summit inside DataStax, we realized it would be a
hot button issue. When I started talking to people in the community, it was
even more of a hot button issue. Having DataStax run the Cassandra Summit
was going to cause a lot of heartache and would further divide the
community with questions and accusations. It’s just much easier to hold a
DataStax Summit so we are just out there plainly and move forward.

What DataStax will be doing different.

We will be moving back to a more regional format instead of the big bang
single event in San Jose starting in 2018. Fun fact. Almost 80% of
attendees of Cassandra Summit were from the Bay Area. That means we have
developers and operators from a lot of other places being excluded which
isn’t cool. We will also be inviting talks from the Cassandra Community.
You don’t have to be a DataStax customer or partner to get on the speaking
list.

If there is some new group or company that launches a Cassandra Summit,
DataStax will happily be a sponsor. There are some for-profit, professional
conference companies like the Linux Foundation out there that just may and
if so, I’ll see you there. After being involved in making the Cassandra
Summit happen for years, I can say it’s no small effort.

There it is. Fire away with your questions, comments. All I ask is keep it
respectful because this is a community of amazing people. You have changed
the world over these years and I know it won’t stop. You know I got a hug
for you wherever we just happen to meet.

Patrick

MemtablePostFlush pending

[ZAIDI, ASAD A]

Hello Folks,

I’m using Cassandra 2.2 on 14 node cluster.

Now a days, I’m observing memtablepostflush pending number going high , this 
happens intermittently. I’m looking if  Is there way to ‘tune’ 
memtablepostflush stage?

Thanks/ASad

Re: rebuild constantly fails, 3.11

[kurt greaves]

cc'ing user back in...

On 12 Aug. 2017 01:55, "kurt greaves"  wrote:

> How much memory do these machines have?  Typically we've found that G1
> isn't worth it until you get to around 24G heaps, and even at that it's not
> really better than CMS. You could try CMS with an 8G heap and 2G new size.
>
> However as the oom is only happening on one node have you ensured there
> are no extra processes running on that node that could be consuming extra
> memory? Note that the oom killer will kill the process with the highest oom
> score, which generally corresponds to the process using the most memory,
> but not necessarily the problem.
>
> Also could you run nodetool info on the problem node and 1 other and dump
> the output in a gist? It would be interesting to see if there is a
> significant difference in off-heap.
>
> On 11 Aug. 2017 17:30, "Micha"  wrote:
>
>> It's an oom issue, the kernel kills the cassandra job.
>> The config was to use offheap buffers and 20G java heap, I changed this
>> to use heap buffers and 16G java heap. I added a  new node yesterday
>> which got streams from 4 other nodes. They all succeeded except on the
>> one node which failed before. This time again the db was killed by the
>> kernel. At the moment I don't know what is the reason here, since the
>> nodes are equal.
>>
>> For me it seems the g1gc is not able to free the memory fast enough.
>> The settings were for  MaxGCPauseMillis=600 and ParallelGCThreads=10
>> ConcGCThreads=10 which maybe are too high since the node has only 8
>> cores..
>> I changed this ParallelGCThreads=8 and ConcGCThreads=2 as is mentioned
>> in the comments of jvm.options
>>
>> Since the bootstrap of the fifth node did not complete I will start it
>> again and check if the memory is still decreasing over time.
>>
>>
>>
>>  Michael
>>
>>
>>
>> On 11.08.2017 01:25, Jeff Jirsa wrote:
>> >
>> >
>> > On 2017-08-08 01:00 (-0700), Micha  wrote:
>> >> Hi,
>> >>
>> >> it seems I'm not able to add add 3 node dc to a 3 node dc. After
>> >> starting the rebuild on a new node, nodetool netstats show it will
>> >> receive 1200 files from node-1 and 5000 from node-2. The stream from
>> >> node-1 completes but the stream from node-2 allways fails, after
>> sending
>> >> ca 4000 files.
>> >>
>> >> After restarting the rebuild it again starts to send the 5000 files.
>> >> The whole cluster is connected via one switch only , no firewall
>> >> between, the networks shows no errors.
>> >> The machines have 8 cores, 32GB RAM and two 1TB discs as raid0.
>> >> the logs show no errors. The size of the data is ca 1TB.
>> >
>> > Is there anything in `dmesg` ?  System logs? Nothing? Is node2 running?
>> Is node3 running?
>> >
>> > -
>> > To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org
>> > For additional commands, e-mail: dev-h...@cassandra.apache.org
>> >
>>
>> -
>> To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org
>> For additional commands, e-mail: dev-h...@cassandra.apache.org
>>
>>

Re: unsubscribe

[Alain RODRIGUEZ]

Hi,

Subhankar, you are probably still around and receiving our mails... As
mentioned in the email footer:

To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org



2017-07-27 7:42 GMT+01:00 subhankar biswas :

>
>
> Thanks and regards,
> Subhankar
>
>
> -
> To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org
> For additional commands, e-mail: user-h...@cassandra.apache.org
>
>

Re: Error Exception in Repair Thread

[Alain RODRIGUEZ]

Hi,

java.lang.InterruptedException
>

I am not sure here, but just a silly thought: did you restart a node during
this repair process? A restarting node could probably create an
interruption on a streaming process.

C*heers,
---
Alain Rodriguez - @arodream - al...@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http://www.thelastpickle.com



2017-07-27 19:50 GMT+01:00 Meg Mara :

> Hello Cassandra Experts!
>
>
>
> I have seen the following errors in the system log when a scheduled
> nodetool repair operation runs on the cluster. Cassandra Version 3.0.10.
> Any thoughts or suggestions are welcome!
>
>
>
> ERROR [Repair#3794:3] 2017-07-27 17:47:22,000 CassandraDaemon.java:207 -
> Exception in thread Thread[Repair#3794:3,5,RMI Runtime]
>
> java.lang.AssertionError: java.lang.InterruptedException
>
> at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.
> extractThrowable(DebuggableThreadPoolExecutor.java:265)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
>
> at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.
> logExceptionsAfterExecute(DebuggableThreadPoolExecutor.java:225)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
>
> at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.
> afterExecute(DebuggableThreadPoolExecutor.java:196)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
>
> at 
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1150)
> ~[na:1.8.0_101]
>
> at 
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> ~[na:1.8.0_101]
>
> at java.lang.Thread.run(Thread.java:745) ~[na:1.8.0_101]
>
> Caused by: java.lang.InterruptedException: null
>
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.
> acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1302)
> ~[na:1.8.0_101]
>
> at com.google.common.util.concurrent.AbstractFuture$
> Sync.get(AbstractFuture.java:285) ~[guava-18.0.jar:na]
>
> at 
> com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:116)
> ~[guava-18.0.jar:na]
>
> at org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.
> extractThrowable(DebuggableThreadPoolExecutor.java:261)
> ~[apache-cassandra-3.0.10.jar:3.0.10]
>
> ... 5 common frames omitted
>
>
>
> Thank you,
>
> Meg Mara
>
>
>

Re: optimal value for native_transport_max_threads

[Alain RODRIGUEZ]

Hi,

There are 2 distinct things indeed, I recommend you the following default
value and tune from there:

max_queued_native_transport_requests=1024

This is the new default value after parch CASSANDRA-11363 -
https://issues.apache.org/jira/secure/attachment/12818636/thread-queue-2.1.txt).
You can always set it in the cassandra-env.sh file with
"-Dcassandra.max_queued_native_transport_requests=1024"

native_transport_max_threads: 128

Default is commented, it's better to control the incoming load explicitely,
128 is a commonly used value -
https://github.com/apache/cassandra/blob/cassandra-3.11.0/conf/cassandra.yaml#L641-L645

Then use 'watch -d nodetool tpstats' or equivalent (monitoring...) on your
nodes and if there is an increasing number of blocked
'Native-Transport-Requests', consider increasing the first value
(max_queued_native_transport_requests=1024)
if your machines can take more load.

For the second parameter you can use something like 'netstats -tupawn |
grep 9042 | grep ESTABLISHED | wc -l' or monitoring again. As long as this
value is lower than 128, you are under the limit of connection. Note that
in recent Native protocol, each connection can handle many simultaneous
requests (128 before V3, 32768 for V3+). See the compatibility matrix for
Native protocols
http://docs.datastax.com/en/developer/java-driver/3.1/manual/native_protocol/
and the connection pooling I was mentioning above
http://docs.datastax.com/en/developer/java-driver/3.1/manual/pooling/.

C*heers,
---
Alain Rodriguez - @arodream - al...@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http://www.thelastpickle.com



2017-08-09 4:49 GMT+01:00 Peng Xiao <2535...@qq.com>:

> Dear All,
>
> any suggestion for optimal value for native_transport_max_threads?
> as per https://issues.apache.org/jira/browse/CASSANDRA-11363,ma
> x_queued_native_transport_requests=4096,how about native_transport_max_
> threads?
>
> Thanks,
> Peng Xiao
>