Re: Can't save Opscenter Dashboard

[Kai Wang]

No they don't.

On Wed, Nov 4, 2015 at 3:42 PM, Sebastian Estevez <
sebastian.este...@datastax.com> wrote:

> Do they come back if you restart opscenterd?
>
> All the best,
>
>
> [image: datastax_logo.png] 
>
> Sebastián Estévez
>
> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>
> [image: linkedin.png]  [image:
> facebook.png]  [image: twitter.png]
>  [image: g+.png]
> 
> 
> 
>
>
> 
>
> DataStax is the fastest, most scalable distributed database technology,
> delivering Apache Cassandra to the world’s most innovative enterprises.
> Datastax is built to be agile, always-on, and predictably scalable to any
> size. With more than 500 customers in 45 countries, DataStax is the
> database technology and transactional backbone of choice for the worlds
> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>
> On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:
>
>> Forgot to mention. I am running OpsCenter 5.2.2.
>>
>> On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:
>>
>>> Hi,
>>>
>>> Today after one of the nodes is rebooted, OpsCenter dashboard doesn't
>>> save anymore. It starts with an empty dashboard with no widget or graph. If
>>> I add some graph/widget, they are being updated fine. But if I refresh the
>>> browser, the dashboard became empty again.
>>>
>>> Also there's no "DEFAULT" tab on the dashboard as the user guide shows.
>>> I am not sure if it was there before.
>>>
>>
>>
>

Re: Can't save Opscenter Dashboard

[Kai Wang]

Forgot to mention. I am running OpsCenter 5.2.2.

On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:

> Hi,
>
> Today after one of the nodes is rebooted, OpsCenter dashboard doesn't save
> anymore. It starts with an empty dashboard with no widget or graph. If I
> add some graph/widget, they are being updated fine. But if I refresh the
> browser, the dashboard became empty again.
>
> Also there's no "DEFAULT" tab on the dashboard as the user guide shows. I
> am not sure if it was there before.
>

Does nodetool cleanup clears tombstones in the CF?

[K F]

Hi,
Quick question, in order for me to purge tombstones on particular nodes if I 
run nodetool cleanup   will that help in purging 
the tombstones from that node?
Thanks.

Re: Doubt regarding consistency-level in Cassandra-2.1.10

[Eric Stevens]

Glad you got it figured out, but I'm confused about the @Version
annotation.  The DataStax Java Driver just handles statements, as far as I
know it's never going to modify statement text.  It sounds like you're
using an entity mapping framework on top of the java driver, which uses
@Version for optimistic locking, and that upgraded the generated statement
to a CAS operation.

On Wed, Nov 4, 2015 at 1:20 AM Ajay Garg  wrote:

> Hi All.
>
> I think we got the root-cause.
>
> One of the fields in one of the class was marked with "@Version"
> annotation, which was causing the Cassandra-Java-Driver to insert "If Not
> Exists" in the insert query, thus invoking SERIAL consistency-level.
>
> We removed the annotation (didn't really need that), and we have not
> observed the error since about an hour or so.
>
>
> Thanks Eric and Bryan for the help !!!
>
>
> Thanks and Regards,
> Ajay
>
> On Wed, Nov 4, 2015 at 8:51 AM, Ajay Garg  wrote:
>
>> Hmm... ok.
>>
>> Ideally, we require ::
>>
>> a)
>> The intra-DC-node-syncing takes place at the statement/query level.
>>
>> b)
>> The inter-DC-node-syncing takes place at cassandra level.
>>
>>
>> That way, we don't spend too much delay at the statement/query level.
>>
>>
>> For the so-called CAS/lightweight transactions, the above are impossible
>> then?
>>
>> On Wed, Nov 4, 2015 at 5:58 AM, Bryan Cheng 
>> wrote:
>>
>>> What Eric means is that SERIAL consistency is a special type of
>>> consistency that is only invoked for a subset of operations: those that use
>>> CAS/lightweight transactions, for example "IF NOT EXISTS" queries.
>>>
>>> The differences between CAS operations and standard operations are
>>> significant and there are large repercussions for tunable consistency. The
>>> amount of time such an operation takes is greatly increased as well; you
>>> may need to increase your internal node-to-node timeouts .
>>>
>>> On Mon, Nov 2, 2015 at 8:01 PM, Ajay Garg 
>>> wrote:
>>>
 Hi Eric,

 I am sorry, but I don't understand.

 If there had been some issue in the configuration, then the
 consistency-issue would be seen everytime (I guess).
 As of now, the error is seen sometimes (probably 30% of times).

 On Mon, Nov 2, 2015 at 10:24 PM, Eric Stevens 
 wrote:

> Serial consistency gets invoked at the protocol level when doing
> lightweight transactions such as CAS operations.  If you're expecting that
> your topology is RF=2, N=2, it seems like some keyspace has RF=3, and so
> there aren't enough nodes available to satisfy serial consistency.
>
> See
> http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_ltwt_transaction_c.html
>
> On Mon, Nov 2, 2015 at 1:29 AM Ajay Garg 
> wrote:
>
>> Hi All.
>>
>> I have a 2*2 Network-Topology Replication setup, and I run my
>> application via DataStax-driver.
>>
>> I frequently get the errors of type ::
>> *Cassandra timeout during write query at consistency SERIAL (3
>> replica were required but only 0 acknowledged the write)*
>>
>> I have already tried passing a "write-options with LOCAL_QUORUM
>> consistency-level" in all create/save statements, but I still get this
>> error.
>>
>> Does something else need to be changed in
>> /etc/cassandra/cassandra.yaml too?
>> Or may be some another place?
>>
>>
>> --
>> Regards,
>> Ajay
>>
>


 --
 Regards,
 Ajay

>>>
>>>
>>
>>
>> --
>> Regards,
>> Ajay
>>
>
>
>
> --
> Regards,
> Ajay
>

Re: Can't save Opscenter Dashboard

[Sebastian Estevez]

Do they come back if you restart opscenterd?

All the best,


[image: datastax_logo.png] 

Sebastián Estévez

Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com

[image: linkedin.png]  [image:
facebook.png]  [image: twitter.png]
 [image: g+.png]







DataStax is the fastest, most scalable distributed database technology,
delivering Apache Cassandra to the world’s most innovative enterprises.
Datastax is built to be agile, always-on, and predictably scalable to any
size. With more than 500 customers in 45 countries, DataStax is the
database technology and transactional backbone of choice for the worlds
most innovative companies such as Netflix, Adobe, Intuit, and eBay.

On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:

> Forgot to mention. I am running OpsCenter 5.2.2.
>
> On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:
>
>> Hi,
>>
>> Today after one of the nodes is rebooted, OpsCenter dashboard doesn't
>> save anymore. It starts with an empty dashboard with no widget or graph. If
>> I add some graph/widget, they are being updated fine. But if I refresh the
>> browser, the dashboard became empty again.
>>
>> Also there's no "DEFAULT" tab on the dashboard as the user guide shows. I
>> am not sure if it was there before.
>>
>
>

Re: Can't save Opscenter Dashboard

[Kai Wang]

I am using Firefox. In web console I saw five messages (excluding Net and
CSS):

The character encoding of the HTML document was not declared. The document
will render with garbled text in some browser configurations if the
document contains characters from outside the US-ASCII range. The character
encoding of the page must be declared in the document or in the transfer
protocol. index.html

Synchronous XMLHttpRequest on the main thread is deprecated because of its
detrimental effects to the end user's experience. For more help
http://xhr.spec.whatwg.org/ dojo.js:110:0

baseurl#makeUrl called without calling setRoot first. ripcord.js:54:61

Use of getAttributeNode() is deprecated. Use getAttribute() instead.
dojo.js:175:0

This site makes use of a SHA-1 Certificate; it's recommended you use
certificates with signature algorithms that use hash functions stronger
than SHA-1.[Learn More] opscenter.datastax.com


On Wed, Nov 4, 2015 at 3:47 PM, Sebastian Estevez <
sebastian.este...@datastax.com> wrote:

> Are there any errors in your javascript console?
>
> All the best,
>
>
> [image: datastax_logo.png] 
>
> Sebastián Estévez
>
> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>
> [image: linkedin.png]  [image:
> facebook.png]  [image: twitter.png]
>  [image: g+.png]
> 
> 
> 
>
>
> 
>
> DataStax is the fastest, most scalable distributed database technology,
> delivering Apache Cassandra to the world’s most innovative enterprises.
> Datastax is built to be agile, always-on, and predictably scalable to any
> size. With more than 500 customers in 45 countries, DataStax is the
> database technology and transactional backbone of choice for the worlds
> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>
> On Wed, Nov 4, 2015 at 3:46 PM, Kai Wang  wrote:
>
>> No they don't.
>>
>> On Wed, Nov 4, 2015 at 3:42 PM, Sebastian Estevez <
>> sebastian.este...@datastax.com> wrote:
>>
>>> Do they come back if you restart opscenterd?
>>>
>>> All the best,
>>>
>>>
>>> [image: datastax_logo.png] 
>>>
>>> Sebastián Estévez
>>>
>>> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>>>
>>> [image: linkedin.png]  [image:
>>> facebook.png]  [image: twitter.png]
>>>  [image: g+.png]
>>> 
>>> 
>>> 
>>>
>>>
>>> 
>>>
>>> DataStax is the fastest, most scalable distributed database technology,
>>> delivering Apache Cassandra to the world’s most innovative enterprises.
>>> Datastax is built to be agile, always-on, and predictably scalable to any
>>> size. With more than 500 customers in 45 countries, DataStax is the
>>> database technology and transactional backbone of choice for the worlds
>>> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>>>
>>> On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:
>>>
 Forgot to mention. I am running OpsCenter 5.2.2.

 On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:

> Hi,
>
> Today after one of the nodes is rebooted, OpsCenter dashboard doesn't
> save anymore. It starts with an empty dashboard with no widget or graph. 
> If
> I add some graph/widget, they are being updated fine. But if I refresh the
> browser, the dashboard became empty again.
>
> Also there's no "DEFAULT" tab on the dashboard as the user guide
> shows. I am not sure if it was there before.
>


>>>
>>
>

Can't save Opscenter Dashboard

[Kai Wang]

Hi,

Today after one of the nodes is rebooted, OpsCenter dashboard doesn't save
anymore. It starts with an empty dashboard with no widget or graph. If I
add some graph/widget, they are being updated fine. But if I refresh the
browser, the dashboard became empty again.

Also there's no "DEFAULT" tab on the dashboard as the user guide shows. I
am not sure if it was there before.

Re: Can't save Opscenter Dashboard

[Sebastian Estevez]

Are there any errors in your javascript console?

All the best,


[image: datastax_logo.png] 

Sebastián Estévez

Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com

[image: linkedin.png]  [image:
facebook.png]  [image: twitter.png]
 [image: g+.png]







DataStax is the fastest, most scalable distributed database technology,
delivering Apache Cassandra to the world’s most innovative enterprises.
Datastax is built to be agile, always-on, and predictably scalable to any
size. With more than 500 customers in 45 countries, DataStax is the
database technology and transactional backbone of choice for the worlds
most innovative companies such as Netflix, Adobe, Intuit, and eBay.

On Wed, Nov 4, 2015 at 3:46 PM, Kai Wang  wrote:

> No they don't.
>
> On Wed, Nov 4, 2015 at 3:42 PM, Sebastian Estevez <
> sebastian.este...@datastax.com> wrote:
>
>> Do they come back if you restart opscenterd?
>>
>> All the best,
>>
>>
>> [image: datastax_logo.png] 
>>
>> Sebastián Estévez
>>
>> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>>
>> [image: linkedin.png]  [image:
>> facebook.png]  [image: twitter.png]
>>  [image: g+.png]
>> 
>> 
>> 
>>
>>
>> 
>>
>> DataStax is the fastest, most scalable distributed database technology,
>> delivering Apache Cassandra to the world’s most innovative enterprises.
>> Datastax is built to be agile, always-on, and predictably scalable to any
>> size. With more than 500 customers in 45 countries, DataStax is the
>> database technology and transactional backbone of choice for the worlds
>> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>>
>> On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:
>>
>>> Forgot to mention. I am running OpsCenter 5.2.2.
>>>
>>> On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:
>>>
 Hi,

 Today after one of the nodes is rebooted, OpsCenter dashboard doesn't
 save anymore. It starts with an empty dashboard with no widget or graph. If
 I add some graph/widget, they are being updated fine. But if I refresh the
 browser, the dashboard became empty again.

 Also there's no "DEFAULT" tab on the dashboard as the user guide shows.
 I am not sure if it was there before.

>>>
>>>
>>
>

Re: Two node cassandra cluster doubts

[Bryan Cheng]

I believe what's going on here is this step:


Select Count (*) From MYTABLE;---> 15 rows

Shut down Node B.

Start Up Node B.

Select Count (*) From MYTABLE;---> 15 rows


To understand why this is an issue, consider the way that consistency is
attempted within Cassandra. With RF=2, (You should really use an odd number
RF and LOCAL_QUORUM so you can tolerate a node failure, but that's another
thing), your write is hitting Node B, and being queued for writing to Node
A via a process called hinted handoff. Normally, this handoff occurs when
Node A returns to the cluster, up to max_hint_window_in_ms later, causing
all writes it missed to be replayed and integrated. However, since Node B
also goes down during this time period, it loses the queued hints and
therefore Node A never gets that write.

You may see this flip flopping due to your query hitting Node A and Node B
alternately (you can use trace to verify this).

Keep in mind that due to Cassandra's architecture, missing writes will
result in inconsistent data. There are mechanisms to help mitigate this,
for example the aforementioned hinted handoff, or read repair. However, at
the end of the day the only way to ensure consistent data is a repair.
These mechanisms cannot operate reliably if the entire cluster goes down-
which happens in your scenario between the above steps.



On Mon, Nov 2, 2015 at 12:46 PM, Luis Miguel  wrote:

> Thanks for your answer!
> I thought that bootstrapping is executed only when you add a node to the
> cluster the first time after that I thought tgat gossip is the method used
> to discover the cluster members againIn my case I thought that it was
> more about a read repair issue.., am I wrong?
>
> --
> Date: Mon, 2 Nov 2015 21:12:20 +0100
> Subject: Re: FW: Two node cassandra cluster doubts
> From: ichi.s...@gmail.com
> To: user@cassandra.apache.org
>
>
> I think that this is a normal behaviour as you shut down your seed and
> then reboot it. You should know that when you start a seed node it doesn't
> do the bootstrapping thing. Which means it doesn't look if there are
> changes in the contents of the tables. In here in your tests, you shut down
> node A before doing the inserts and started it after. So you node A doesn't
> have the new rows you inserted. And yes it is normal to have  different
> values of your query each time. Because the coordinator node changes and
> therfore  the query is executed each time on a different node ( when  node
> B answers you've got 15 rows and WHE  node A does you have 10 rows)
> Le 2 nov. 2015 19:22, "Luis Miguel"  a écrit :
>
> Hello!
>
> I have set a cassandra cluster with two nodes, Node A  and Node B --> RF=2,
> Read CL=1 and Write CL = 1;
>
> Node A is seed...
>
>
> At first everything is working well, when I add/delete/update entries on
> Node A, everything is replicated on Node B and vice-versa, even if I shut
> down node A, and I made new insertions on Node B meanwhile, and After that
> I start up node A again Cassandra recovers OKBUT there is ONE case when
> this situation fails I am going to describe the process:
>
> Node A and Node B are sync.
>
> Select Count (*) From MYTABLE;---> 10 rows
>
> Shut down Node A.
>
> Made some inserts on Node B.
>
> Select Count (*) From MYTABLE;---> 15 rows
>
> Shut down Node B.
>
> Start Up Node B.
>
> Select Count (*) From MYTABLE;---> 15 rows
>
> (Everything Ok, yet).
>
> Start Up Node A.
>
> Select Count (*) From MYTABLE;---> 10 rows (uhmmm...this is weird...check
> it again)
> Select Count (*) From MYTABLE;---> 15 rows  (wow!..this is correct, lets
> try again)
> Select Count (*) From MYTABLE;---> 10 rows (Ok...values are dancing)
>
> If I made the same queries on NODE B it Behaves the same way and it
> only is solved with a nodetool repair...but I would prefer an automatic
> fail-over...
>
> is there any way to avoid this??? or a nodetool repair execution is
> mandatory???
>
> Thanks in advance!!!
>
>

Re: Can't save Opscenter Dashboard

[Kai Wang]

Reinstalling OpsCenter didn't fix it. Previously I thought the graphs were
updated but actually they were just stalled. I need to refresh and re-add
the graph to see the new metrics. Other information such as activities and
Nodes are updating fine.

On Wed, Nov 4, 2015 at 3:58 PM, Kai Wang  wrote:

> I am using Firefox. In web console I saw five messages (excluding Net and
> CSS):
>
> The character encoding of the HTML document was not declared. The document
> will render with garbled text in some browser configurations if the
> document contains characters from outside the US-ASCII range. The character
> encoding of the page must be declared in the document or in the transfer
> protocol. index.html
>
> Synchronous XMLHttpRequest on the main thread is deprecated because of its
> detrimental effects to the end user's experience. For more help
> http://xhr.spec.whatwg.org/ dojo.js:110:0
>
> baseurl#makeUrl called without calling setRoot first. ripcord.js:54:61
>
> Use of getAttributeNode() is deprecated. Use getAttribute() instead.
> dojo.js:175:0
>
> This site makes use of a SHA-1 Certificate; it's recommended you use
> certificates with signature algorithms that use hash functions stronger
> than SHA-1.[Learn More] opscenter.datastax.com
>
>
> On Wed, Nov 4, 2015 at 3:47 PM, Sebastian Estevez <
> sebastian.este...@datastax.com> wrote:
>
>> Are there any errors in your javascript console?
>>
>> All the best,
>>
>>
>> [image: datastax_logo.png] 
>>
>> Sebastián Estévez
>>
>> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>>
>> [image: linkedin.png]  [image:
>> facebook.png]  [image: twitter.png]
>>  [image: g+.png]
>> 
>> 
>> 
>>
>>
>> 
>>
>> DataStax is the fastest, most scalable distributed database technology,
>> delivering Apache Cassandra to the world’s most innovative enterprises.
>> Datastax is built to be agile, always-on, and predictably scalable to any
>> size. With more than 500 customers in 45 countries, DataStax is the
>> database technology and transactional backbone of choice for the worlds
>> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>>
>> On Wed, Nov 4, 2015 at 3:46 PM, Kai Wang  wrote:
>>
>>> No they don't.
>>>
>>> On Wed, Nov 4, 2015 at 3:42 PM, Sebastian Estevez <
>>> sebastian.este...@datastax.com> wrote:
>>>
 Do they come back if you restart opscenterd?

 All the best,


 [image: datastax_logo.png] 

 Sebastián Estévez

 Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com

 [image: linkedin.png]  [image:
 facebook.png]  [image: twitter.png]
  [image: g+.png]
 
 
 


 

 DataStax is the fastest, most scalable distributed database
 technology, delivering Apache Cassandra to the world’s most innovative
 enterprises. Datastax is built to be agile, always-on, and predictably
 scalable to any size. With more than 500 customers in 45 countries, 
 DataStax
 is the database technology and transactional backbone of choice for the
 worlds most innovative companies such as Netflix, Adobe, Intuit, and eBay.

 On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:

> Forgot to mention. I am running OpsCenter 5.2.2.
>
> On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:
>
>> Hi,
>>
>> Today after one of the nodes is rebooted, OpsCenter dashboard doesn't
>> save anymore. It starts with an empty dashboard with no widget or graph. 
>> If
>> I add some graph/widget, they are being updated fine. But if I refresh 
>> the
>> browser, the dashboard became empty again.
>>
>> Also there's no "DEFAULT" tab on the dashboard as the user guide
>> shows. I am not sure if it was there before.
>>
>
>

>>>
>>
>

Re: Does datastax java driver works with ipv6 address?

[Michael Shuler]

On 11/04/2015 11:17 AM, Dikang Gu wrote:

I have ipv6 only cassandra cluster, and I'm trying to connect to it
using java driver, like:

Inet6Address inet6 = (Inet6Address) 
InetAddress.getByName("2401:db00:0011:60ed:face::0031:");
cluster = Cluster.builder().addContactPointsWithPorts(Arrays.asList(new 
InetSocketAddress(inet6,9042))).build();
session =cluster.connect(CASSANDRA_KEYSPACE);

But it failed to connect to the cassandra, looks like the java driver
does not parse the ipv6 address correctly, exceptions are:




Open a JIRA bug report for the java driver at:

  https://datastax-oss.atlassian.net/browse/JAVA

As for IPv6 testing for Cassandra in general, it has been brought up, 
but little testing is done at this time. If you have some contributions 
to be made in this area, I'm sure they would be greatly appreciated. You 
are in a relatively unique position with an IPv6-only cluster, so your 
input is valuable.



https://issues.apache.org/jira/issues/?jql=project%20%3D%20CASSANDRA%20AND%20text%20~%20ipv6%20AND%20status%20!%3D%20Resolved

--
Kind regards,
Michael

Re: Can't save Opscenter Dashboard

[Kai Wang]

Finally I got it working. I used to have auth information inside
address.yaml. I moved everything except for stomp_interface inside
address.yaml to [agent_config] section of cluster_name.conf and restarted
opscenterd and datastax-agent on all nodes. That seemed to fix the problem.

On Wed, Nov 4, 2015 at 5:36 PM, Kai Wang  wrote:

> Reinstalling OpsCenter didn't fix it. Previously I thought the graphs were
> updated but actually they were just stalled. I need to refresh and re-add
> the graph to see the new metrics. Other information such as activities and
> Nodes are updating fine.
>
> On Wed, Nov 4, 2015 at 3:58 PM, Kai Wang  wrote:
>
>> I am using Firefox. In web console I saw five messages (excluding Net and
>> CSS):
>>
>> The character encoding of the HTML document was not declared. The
>> document will render with garbled text in some browser configurations if
>> the document contains characters from outside the US-ASCII range. The
>> character encoding of the page must be declared in the document or in the
>> transfer protocol. index.html
>>
>> Synchronous XMLHttpRequest on the main thread is deprecated because of
>> its detrimental effects to the end user's experience. For more help
>> http://xhr.spec.whatwg.org/ dojo.js:110:0
>>
>> baseurl#makeUrl called without calling setRoot first. ripcord.js:54:61
>>
>> Use of getAttributeNode() is deprecated. Use getAttribute() instead.
>> dojo.js:175:0
>>
>> This site makes use of a SHA-1 Certificate; it's recommended you use
>> certificates with signature algorithms that use hash functions stronger
>> than SHA-1.[Learn More] opscenter.datastax.com
>>
>>
>> On Wed, Nov 4, 2015 at 3:47 PM, Sebastian Estevez <
>> sebastian.este...@datastax.com> wrote:
>>
>>> Are there any errors in your javascript console?
>>>
>>> All the best,
>>>
>>>
>>> [image: datastax_logo.png] 
>>>
>>> Sebastián Estévez
>>>
>>> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>>>
>>> [image: linkedin.png]  [image:
>>> facebook.png]  [image: twitter.png]
>>>  [image: g+.png]
>>> 
>>> 
>>> 
>>>
>>>
>>> 
>>>
>>> DataStax is the fastest, most scalable distributed database technology,
>>> delivering Apache Cassandra to the world’s most innovative enterprises.
>>> Datastax is built to be agile, always-on, and predictably scalable to any
>>> size. With more than 500 customers in 45 countries, DataStax is the
>>> database technology and transactional backbone of choice for the worlds
>>> most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>>>
>>> On Wed, Nov 4, 2015 at 3:46 PM, Kai Wang  wrote:
>>>
 No they don't.

 On Wed, Nov 4, 2015 at 3:42 PM, Sebastian Estevez <
 sebastian.este...@datastax.com> wrote:

> Do they come back if you restart opscenterd?
>
> All the best,
>
>
> [image: datastax_logo.png] 
>
> Sebastián Estévez
>
> Solutions Architect | 954 905 8615 | sebastian.este...@datastax.com
>
> [image: linkedin.png]  [image:
> facebook.png]  [image: twitter.png]
>  [image: g+.png]
> 
> 
> 
>
>
> 
>
> DataStax is the fastest, most scalable distributed database
> technology, delivering Apache Cassandra to the world’s most innovative
> enterprises. Datastax is built to be agile, always-on, and predictably
> scalable to any size. With more than 500 customers in 45 countries, 
> DataStax
> is the database technology and transactional backbone of choice for the
> worlds most innovative companies such as Netflix, Adobe, Intuit, and eBay.
>
> On Wed, Nov 4, 2015 at 3:41 PM, Kai Wang  wrote:
>
>> Forgot to mention. I am running OpsCenter 5.2.2.
>>
>> On Wed, Nov 4, 2015 at 3:39 PM, Kai Wang  wrote:
>>
>>> Hi,
>>>
>>> Today after one of the nodes is rebooted, OpsCenter dashboard
>>> doesn't save anymore. It starts with an empty dashboard with no widget 
>>> or
>>> graph. If I add some graph/widget, they are being updated fine. But if I
>>> refresh the browser, the dashboard became empty again.
>>>
>>> Also there's no "DEFAULT" tab on the dashboard as the user guide
>>> shows. I am not sure if it was there before.
>>>
>>
>>
>

>>>
>>
>

回复：Can't save Opscenter Dashboard

[qihuang.zheng]

We have this problem with version 5.2.0. so we decide to update to 5.2.2
But this problem seems remain. We solve this by totally delele relate agent 
file and process and restart. just like first time install.


sudo kill -9 `ps -ef|grep datastax_agent_monitor | head -1 |awk '{print $2}'`  \
sudo kill -9 `cat /var/run/datastax-agent/datastax-agent.pid`  \
sudo rm -rf /var/lib/datastax-agent  \
sudo rm -rf /usr/share/datastax-agent


qihuang.zheng


原始邮件
发件人:Kai wangdep...@gmail.com
收件人:useru...@cassandra.apache.org
发送时间:2015年11月5日(周四) 04:39
主题:Can't save Opscenter Dashboard


Hi,


Today after one of the nodes is rebooted, OpsCenter dashboard doesn't save 
anymore. It starts with an empty dashboard with no widget or graph. If I add 
some graph/widget, they are being updated fine. But if I refresh the browser, 
the dashboard became empty again.


Also there's no "DEFAULT" tab on the dashboard as the user guide shows. I am 
not sure if it was there before.

Re: Does datastax java driver works with ipv6 address?

[Dikang Gu]

Thanks Michael,

Actually I find the problem is with the sever setup, I put "rpc_address:
0.0.0.0" in the config, and I find the sever bind to the address like this:

tcp0  0 :::9160 :::*
 LISTEN  2411582/java
tcp0  0 :::0.0.0.0:9042 :::*
 LISTEN  2411582/java

So using the sever ip "2401:db00:11:60ed:face:0:31:0", I can connect to the
thrift port 9160, but not the native port 9042. Do you know the reason for
this?

Thanks
Dikang.


On Wed, Nov 4, 2015 at 12:29 PM, Michael Shuler 
wrote:

> On 11/04/2015 11:17 AM, Dikang Gu wrote:
>
>> I have ipv6 only cassandra cluster, and I'm trying to connect to it
>> using java driver, like:
>>
>> Inet6Address inet6 = (Inet6Address)
>> InetAddress.getByName("2401:db00:0011:60ed:face::0031:");
>> cluster = Cluster.builder().addContactPointsWithPorts(Arrays.asList(new
>> InetSocketAddress(inet6,9042))).build();
>> session =cluster.connect(CASSANDRA_KEYSPACE);
>>
>> But it failed to connect to the cassandra, looks like the java driver
>> does not parse the ipv6 address correctly, exceptions are:
>>
>> 
>
> Open a JIRA bug report for the java driver at:
>
>   https://datastax-oss.atlassian.net/browse/JAVA
>
> As for IPv6 testing for Cassandra in general, it has been brought up, but
> little testing is done at this time. If you have some contributions to be
> made in this area, I'm sure they would be greatly appreciated. You are in a
> relatively unique position with an IPv6-only cluster, so your input is
> valuable.
>
>
>
> https://issues.apache.org/jira/issues/?jql=project%20%3D%20CASSANDRA%20AND%20text%20~%20ipv6%20AND%20status%20!%3D%20Resolved
>
> --
> Kind regards,
> Michael
>
>


-- 
Dikang

Question for datastax java Driver

[Dikang Gu]

Hi there,

Right now, it seems if I add a contact point like this:

cluster = Cluster.builder().addContactPoint().build();

When client is connected to the cluster, client will fetch the addresses
for all the nodes in the cluster, and try to connect to them.

I'm wondering can I disable the behavior? I mean I just want each client to
connect to one or several contact point, not connect to all of the nodes,
am I able to do this?

Thanks.
-- 
Dikang

Does datastax java driver works with ipv6 address?

[Dikang Gu]

Hi there,

I have ipv6 only cassandra cluster, and I'm trying to connect to it using
java driver, like:

Inet6Address inet6 = (Inet6Address)
InetAddress.getByName("2401:db00:0011:60ed:face::0031:");
cluster = Cluster.builder().addContactPointsWithPorts(Arrays.asList(new
InetSocketAddress(inet6, 9042))).build();
session = cluster.connect(CASSANDRA_KEYSPACE);

But it failed to connect to the cassandra, looks like the java driver does
not parse the ipv6 address correctly, exceptions are:

337 [cluster1-nio-worker-0] DEBUG com.datastax.driver.core.Connection  -
Connection[/2401:db00:11:60ed:face:0:31:0:9042-1, inFlight=0, closed=true]
closing connection
339 [main] DEBUG com.datastax.driver.core.ControlConnection  - [Control
connection] error on /2401:db00:11:60ed:face:0:31:0:9042 connection, no
more host to try
com.datastax.driver.core.TransportException:
[/2401:db00:11:60ed:face:0:31:0:9042] Cannot connect
at
com.datastax.driver.core.Connection$1.operationComplete(Connection.java:156)
at
com.datastax.driver.core.Connection$1.operationComplete(Connection.java:139)
at
io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:680)
at
io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:603)
at
io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:563)
at
io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:424)
at
io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.fulfillConnectPromise(AbstractNioChannel.java:268)
at
io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:284)
at
io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:528)
at
io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)
at
io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
at
io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.net.ConnectException: Connection refused:
/2401:db00:11:60ed:face:0:31:0:9042
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:735)
at
io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:224)
at
io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:281)
... 6 more
342 [main] DEBUG com.datastax.driver.core.AbstractReconnectionHandler  -
First reconnection scheduled in 1000ms
342 [main] DEBUG com.datastax.driver.core.AbstractReconnectionHandler  -
Becoming the active handler
342 [main] DEBUG com.datastax.driver.core.Cluster  - Shutting down
Exception in thread "main"
com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s)
tried for query failed (tried: /2401:db00:11:60ed:face:0:31:0:9042
(com.datastax.driver.core.TransportException:
[/2401:db00:11:60ed:face:0:31:0:9042] Cannot connect))
at
com.datastax.driver.core.ControlConnection.reconnectInternal(ControlConnection.java:223)
at
com.datastax.driver.core.ControlConnection.connect(ControlConnection.java:78)
at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1272)
at com.datastax.driver.core.Cluster.init(Cluster.java:158)
at com.datastax.driver.core.Cluster.connect(Cluster.java:248)
at com.datastax.driver.core.Cluster.connect(Cluster.java:281)

-- 
Dikang

Re: Doubt regarding consistency-level in Cassandra-2.1.10

[Ajay Garg]

Hi All.

I think we got the root-cause.

One of the fields in one of the class was marked with "@Version"
annotation, which was causing the Cassandra-Java-Driver to insert "If Not
Exists" in the insert query, thus invoking SERIAL consistency-level.

We removed the annotation (didn't really need that), and we have not
observed the error since about an hour or so.


Thanks Eric and Bryan for the help !!!


Thanks and Regards,
Ajay

On Wed, Nov 4, 2015 at 8:51 AM, Ajay Garg  wrote:

> Hmm... ok.
>
> Ideally, we require ::
>
> a)
> The intra-DC-node-syncing takes place at the statement/query level.
>
> b)
> The inter-DC-node-syncing takes place at cassandra level.
>
>
> That way, we don't spend too much delay at the statement/query level.
>
>
> For the so-called CAS/lightweight transactions, the above are impossible
> then?
>
> On Wed, Nov 4, 2015 at 5:58 AM, Bryan Cheng  wrote:
>
>> What Eric means is that SERIAL consistency is a special type of
>> consistency that is only invoked for a subset of operations: those that use
>> CAS/lightweight transactions, for example "IF NOT EXISTS" queries.
>>
>> The differences between CAS operations and standard operations are
>> significant and there are large repercussions for tunable consistency. The
>> amount of time such an operation takes is greatly increased as well; you
>> may need to increase your internal node-to-node timeouts .
>>
>> On Mon, Nov 2, 2015 at 8:01 PM, Ajay Garg  wrote:
>>
>>> Hi Eric,
>>>
>>> I am sorry, but I don't understand.
>>>
>>> If there had been some issue in the configuration, then the
>>> consistency-issue would be seen everytime (I guess).
>>> As of now, the error is seen sometimes (probably 30% of times).
>>>
>>> On Mon, Nov 2, 2015 at 10:24 PM, Eric Stevens  wrote:
>>>
 Serial consistency gets invoked at the protocol level when doing
 lightweight transactions such as CAS operations.  If you're expecting that
 your topology is RF=2, N=2, it seems like some keyspace has RF=3, and so
 there aren't enough nodes available to satisfy serial consistency.

 See
 http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_ltwt_transaction_c.html

 On Mon, Nov 2, 2015 at 1:29 AM Ajay Garg 
 wrote:

> Hi All.
>
> I have a 2*2 Network-Topology Replication setup, and I run my
> application via DataStax-driver.
>
> I frequently get the errors of type ::
> *Cassandra timeout during write query at consistency SERIAL (3 replica
> were required but only 0 acknowledged the write)*
>
> I have already tried passing a "write-options with LOCAL_QUORUM
> consistency-level" in all create/save statements, but I still get this
> error.
>
> Does something else need to be changed in
> /etc/cassandra/cassandra.yaml too?
> Or may be some another place?
>
>
> --
> Regards,
> Ajay
>

>>>
>>>
>>> --
>>> Regards,
>>> Ajay
>>>
>>
>>
>
>
> --
> Regards,
> Ajay
>



-- 
Regards,
Ajay

Re: compression cpu overhead

[Dan Kinder]

To clarify, writes have no *immediate* cpu cost from adding the write to
the memtable, however the compression overhead cost is paid when writing
out a new SSTable (whether from flushing a memtable or compacting), correct?

So it sounds like when reads >> writes then Tushar's comments are accurate,
but for a high write workload flushing and compactions would create most of
the overhead.

On Tue, Nov 3, 2015 at 6:03 PM, Jon Haddad 
wrote:

> You won't see any overhead on writes because you don't actually write to
> sstables when performing a write.  Just the commit log & memtable.
> Memtables are flushes asynchronously.
>
> On Nov 4, 2015, at 1:57 AM, Tushar Agrawal 
> wrote:
>
> For writes it's negligible. For reads it makes a significant difference
> for high tps and low latency workload. You would see up to 3x higher cpu
> with LZ4 vs no compression. It would be different for different h/w
> configurations.
>
>
> Thanks,
> Tushar
> (Sent from iPhone)
>
> On Nov 3, 2015, at 5:51 PM, Dan Kinder  wrote:
>
> Most concerned about write since that's where most of the cost is, but
> perf numbers for a any workload mix would be helpful.
>
> On Tue, Nov 3, 2015 at 3:48 PM, Graham Sanderson  wrote:
>
>> On read or write?
>>
>> https://issues.apache.org/jira/browse/CASSANDRA-7039 and friends in 2.2
>> should make some difference, I didn’t immediately find perf numbers though.
>>
>> On Nov 3, 2015, at 5:42 PM, Dan Kinder  wrote:
>>
>> Hey all,
>>
>> Just wondering if anyone has done seen or done any benchmarking for the
>> actual CPU overhead added by various compression algorithms in Cassandra
>> (at least LZ4) vs no compression. Clearly this is going to be workload
>> dependent but even a rough gauge would be helpful (ex. "Turning on LZ4
>> compression increases my CPU load by ~2x")
>>
>> -dan
>>
>>
>>
>
>
> --
> Dan Kinder
> Senior Software Engineer
> Turnitin – www.turnitin.com
> dkin...@turnitin.com
>
>
>


-- 
Dan Kinder
Senior Software Engineer
Turnitin – www.turnitin.com
dkin...@turnitin.com