Re: Materialised view for sets of UUID

The question is what matters and how big cardinality is. 1. MV updates are atomic 2. Updates on 2 tables are not. You'd require a logged batch to ensure atomicity and so the write performance is also a little bit lower than without batches 3. If you have a hand full of groups per user,

Materialised view for sets of UUID

Hallöchen! In RDBMS terms, I have a n:m relationship between "users" and "groups". I need to answer the questions "who's in that group" and "in which groups is he". In my Cassandra DB, this looks like this: CREATE TABLE users ( id uuid PRIMARY KEY, groups_member set

RE: Handling Leap second delay

Hi , Attached conversation can be of some help to you. Regards Amit Singh From: Sanjeev T [mailto:san...@gmail.com] Sent: Wednesday, December 21, 2016 9:24 AM To: user@cassandra.apache.org Subject: Handling Leap second delay Hi, Can some of you share points on, the versions and handling leap

Re: Join_ring=false Use Cases

Thanks All !! I think the intent of the JIRA https://issues.apache.org/ jira/browse/CASSANDRA-6961 was to primarily deal with stale information after outages and give opportunity for repairing the data before a node joins the cluster. If a node started with join_ring=false doesn't accept writes

Re: Python Upgrade to 2.7

Python is missing the zlib module. The solution to this problem depends on whether you've compiled Python from source, or are using a distribution package. Googling the error "can't decompress data; zlib not available" should provide an answer on how to solve this. If not, send us more details

Re: Processing time series data in order

The batch size can be large, so in memory ordering isn't an option, unfortunately. On Thu, Dec 22, 2016 at 7:09 AM, Jesse Hodges wrote: > Depending on the expected max out of order window, why not order them in > memory? Then you don't need to reread from Cassandra, in

Re: Cassandra cluster performance

Given you’re using replication factor 1 (so each piece of data is only going to get written to one node) something definitely seems wrong. Some questions/ideas: - are there any errors in the Cassandra logs or are you seeing any errors at the client? - is your test data distributed across your

Re: Not timing out some queries (Java driver)

cassandra.yaml has various timeouts such as read_request_timeout, range_request_timeout, write_request_timeout, etc. The driver does as well (via Cluster -> Configuration -> SocketOptions -> setReadTimeoutMillis). Not sure if you can (or would want to) set them to "forever", but it's a starting

Re: Processing time series data in order

Depending on the expected max out of order window, why not order them in memory? Then you don't need to reread from Cassandra, in case of a problem you can reread data from Kafka. -Jesse > On Dec 21, 2016, at 7:24 PM, Ali Akhtar wrote: > > - I'm receiving a batch of

Processing time series data in order

- I'm receiving a batch of messages to a Kafka topic. Each message has a timestamp, however the messages can arrive / get processed out of order. I.e event 1's timestamp could've been a few seconds before event 2, and event 2 could still get processed before event 1. - I know the number of

Not timing out some queries (Java driver)

I have some queries which need to be processed in a consistent manner. I'm setting the consistently level = ALL option on these queries. However, I've noticed that sometimes these queries fail because of a timeout (2 seconds). In my use case, for certain queries, I want them to never time out

Re: Cassandra cluster performance

Hi, - Consistency level is set to ONE - Keyspace definition: "CREATE KEYSPACE IF NOT EXISTS onem2m " + "WITH replication = " + "{ 'class' : 'SimpleStrategy', 'replication_factor' : 1}"; - yes, the client is on separate VM - In our project we use

Python Upgrade to 2.7

I am running Cassandra 2.1.14. Upgraded to Python 2.7 from 2.6.6 and getting the following error with CQLSH. --- Python Cassandra driver not installed, or not on PYTHONPATH. You might try "pip install cassandra-driver". Python: /opt/isv/python27/bin/python Error: can't decompress data; zlib

Re: Cassandra cluster performance

You would expect some drop when moving to single multiple nodes but on the face of it that feels extreme to me (although I’ve never personally tested the difference). Some questions that might help provide an answer: - what consistency level are you using for the test? - what is your keyspace

Cassandra cluster performance

Hi all, I’m working on a project and we have Java benchmark test for testing the performance when using Cassandra database. Create operation on a single node Cassandra cluster is about 15K operations per second. Problem we have is when I set up cluster with 2 or more nodes (each of them are on

Re: Query on Cassandra clusters

Thank you Alain for the detailed explanation. To answer you question on Java version, JVM settings and Memory usage. We are using using 1.8.0_45. precisely >java -version java version "1.8.0_45" Java(TM) SE Runtime Environment (build 1.8.0_45-b14) Java HotSpot(TM) 64-Bit Server VM (build

Advice in upgrade plan from 1.2.18 to 2.2.8

Hi everyone, I have 2 C* DCs with 12 nodes in each running 1.2.18. I plan to upgrade them to 2.2.latest and wanted to run by you experts my plan. 1. Install 2.0.latest on one node at a time, start and wait for it to join the ring. 2. Run upgradesstables on this node. 3. Repeat Step

Openstack and Cassandra

Hi Everyone, I am looking into the option of deploying a Cassandra cluster on Openstack nodes instead of physical nodes due to resource management considerations. Does anyone has any insights regarding this? Can this combination work properly? Since the disks (HDDs) are part of one physical

Re: High CPU on nodes

https://issues.apache.org/jira/browse/CASSANDRA-6908 Disable DynamicSnitch by adding the following to cassandra.yaml (it is a not in the file by default): dynamic_snitch: false On Wed, Dec 21, 2016 at 8:40 AM, Anubhav Kale wrote: > CIL > > > > *From:* Alain

RE: High CPU on nodes

CIL From: Alain RODRIGUEZ [mailto:arodr...@gmail.com] Sent: Saturday, December 17, 2016 5:18 AM To: user@cassandra.apache.org Subject: Re: High CPU on nodes Hi, What does 'nodetool netstats' looks like on those nodes? Its not doing any streaming. we have 30GB heap How is the JVM / GC doing?

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

Reading that article the only conclusion I can reach (unless I'm misreading) is that all the stuff that was never free is still not free - the change is that Oracle may actually be interested in the fact that some are using non-free products for free. Pretty much a non-story, it seems like. On

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

On 12/21/2016 08:38 AM, Eric Evans wrote: > I don't really have any opinions on Oracle per say, but Cassandra is a > Free Software project and I would prefer that we not depend on > commercial software, (and that's kind of what we have here, an > implicit dependency). Just a bit of clarification.

Re: Choosing a compaction strategy (TWCS)

Just want to bump this thread if possible... having trouble ferreting out the specifics of TWCS configuration, google's not being particularly helpful. If tombstone compactions are disabled by default in TWCS, does one enable them by setting values for tombstone_compaction_interval and

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

On Tue, Dec 20, 2016 at 11:55 PM, Kant Kodali wrote: > Looking at this > http://www.theregister.co.uk/2016/12/16/oracle_targets_java_users_non_compliance/?mt=1481919461669 > I don't know why Cassandra recommends Oracle JVM? The long answer probably dates back to before the

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

On Wednesday, December 21, 2016, Kant Kodali wrote: > https://www.youtube.com/watch?v=9ei-rbULWoA > > On Wed, Dec 21, 2016 at 2:59 AM, Kant Kodali > wrote: > >>

Re: Query on Cassandra clusters

Hi Sumit, 1. I have a Cassandra cluster with 11 nodes, 5 of which have Cassandra > version 3.0.3 and then newer 5 nodes have 3.6.0 version. I strongly recommend to: - Stick with one version of Apache Cassandra per cluster. - Always be as close as possible from the last minor release of

Re: iostat -like tool to parse 'nodetool cfstats'

Hi Kevin, > nodetool cfstats has some valuable data but what I would like is a 1 > minute delta. And you are right in what you think would be useful. In many cases variation is a way more informative than an absolute value indeed. I have a doubt regarding your approach though. I want to see

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

https://www.youtube.com/watch?v=9ei-rbULWoA On Wed, Dec 21, 2016 at 2:59 AM, Kant Kodali wrote: > https://www.elastic.co/guide/en/elasticsearch/guide/ > current/_java_virtual_machine.html > > On Wed, Dec 21, 2016 at 2:58 AM, Kant Kodali wrote: > >> The

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

https://www.elastic.co/guide/en/elasticsearch/guide/current/_java_virtual_machine.html On Wed, Dec 21, 2016 at 2:58 AM, Kant Kodali wrote: > The fact is Oracle is horrible :) > > > On Wed, Dec 21, 2016 at 2:54 AM, Brice Dutheil > wrote: > >> Let's

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

The fact is Oracle is horrible :) On Wed, Dec 21, 2016 at 2:54 AM, Brice Dutheil wrote: > Let's not debate opinion on the Oracle stewardship here, we certainly have > different views that come from different experiences. > > Let's discuss facts instead :) > > -- Brice

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

Let's not debate opinion on the Oracle stewardship here, we certainly have different views that come from different experiences. Let's discuss facts instead :) -- Brice On Wed, Dec 21, 2016 at 11:34 AM, Kant Kodali wrote: > yeah well I don't think Oracle is treating Java

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

yeah well I don't think Oracle is treating Java the way Google is treating Go and I am not a big fan of Go mainly because I understand the JVM is far more robust than anything that is out there. "Oracle just doesn't understand open source" These are the words from James Gosling himself I do

Re: Why does Cassandra recommends Oracle JVM instead of OpenJDK?

The problem described in this article is different than what you have on your servers and I’ll add this article should be reaad with caution, as The Register is known for sensationalism. The article itself has no substantial proof or enough details. In my opinion this article is clickbait. Anyway

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