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  • How do I take the advantage of the variable column key/value structure of Cassandra

    - by icejade
    If I have to predefine all the columns, how do I take the advantage of the variable column key/value structure of cassandra? If I use update table command, it will insert null for all the rows which don't have that column. This is same as relational DB. For example, for contact column family, I have name, phone, email. I have 100 contacts have all 3 field. Then number 101 contact has skype id which I want to add. If I use insert statement, it won't let me add skypeid since it's not defined in the CF. So I have to run alter statement to change the CF, then all the first 100 contacts will have a null field for each of them.

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  • UUID Cassandra.

    - by Sandeep
    Hi all, I am new to Cassandra. I am trying to insert some values to the columnfamily. The definition of columnfamily in the config file is as follows. <ColumnFamily Name="CommandQueue" ColumnType="Super" CompareWith="TimeUUIDType" CompareSubcolumnsWith="UTF8Type"/> When ever I try to insert values to I always get "InvalidRequestException(why: UUIDs must be exactly 16 bytes)". I am using batch_mutate() to insert column. How can I insert values to the column family.

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  • Mapping Cassandra Super Columns

    - by Laubstein
    Hello dudes, I guess everybody that played with Cassandra already read this article. I trying to create my schema on CassandraCli, but I am having a lot of problems, can someone guide me to the right way? I am trying to create a similar structure like the Comments column family from the article. In CassandraCli terminal I type: create column family posts with column_type = ‘Super’ and comparator = ‘AsciiType’ and subcomparator = TimeUUIDType; It works fine, there is no doc telling me that if I add a column_metadata attribute those will be for the super columns cause my column family is of type super, i can’t find if it is true so: create column family posts with column_type = ‘Super’ and comparator = ‘AsciiType’ and subcomparator = ‘TimeUUIDType’ and column_metadata = [{column_name:'body'}]; I am trying to create the same as the comment column family of the article, but when i try to populate set posts['post1'][timeuuid()][body] = ‘Hello I am Goku!’; i got: Invalid UUID string: body I guess because i chose the subcomparator be of type timeuuid and the body is a string, it should be a timeuuid, so HOW my columns inside the super column which is the type timeuuid could holds columns with string type names as the comments of the article are created? Thanks

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  • Cassandra Batch_insert example in C#.net

    - by Sandeep
    Can any one please give me an example on how to work on Cassandra batch_insert in C# thrift client? If possible please let me know where am I going wrong in the following code. Dictionary dictionary = new Dictionary(); Dictionary subColumns = new Dictionary(); List listOfMutations = new List(); listOfMutations.Add(new Mutation() { Column_or_supercolumn = new ColumnOrSuperColumn() { Column = new Column() { Name = utf8Encoding.GetBytes("AA"), Value = utf8Encoding.GetBytes("Answer Automation"), Timestamp = timeStamp } } }); listOfMutations.Add(new Mutation() { Column_or_supercolumn = new ColumnOrSuperColumn() { Column = new Column() { Name = utf8Encoding.GetBytes("CT"), Value = utf8Encoding.GetBytes("Call Tracker"), Timestamp = timeStamp } } }); listOfMutations.Add( new Mutation() { Column_or_supercolumn = new ColumnOrSuperColumn() { Column = new Column() { Name = utf8Encoding.GetBytes("TL"), Value = utf8Encoding.GetBytes("Track That Lead"), Timestamp = timeStamp } } }); SuperColumn superColumn = new SuperColumn() { Name=utf8Encoding.GetBytes("Indatus") }; subColumns.Add("Super1", listOfMutations); dictionary.Add("Indatus", subColumns); client.batch_mutate("Keyspace1",dictionary, ConsistencyLevel.ONE); I understand that SuperColumn struct expects List but I does not have a list of Columns. Rather I have List. Thanks in Advance.

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  • Opscenter repair service times out. ERROR: Requested range intersects a local range [...]

    - by jlemire-zs
    My production cluster had the repair service enabled since april 16th with the default 9 days time to completion and repairs would complete properly. However, since may 22nd, it is being disabled automatically by Opscenter: From /var/log/opscenter/opscenterd.log: [...] 2014-06-03 21:13:47-0400 [zs_prod] ERROR: Repair task (<Node 10.1.0.22='6417880425364517165'>, (-4019838962446882275L, -4006140687792135587L), set(['zs_logging', 'OpsCenter'])) timed out after 3600 seconds. 2014-06-03 22:16:44-0400 [zs_prod] ERROR: Repair task (<Node 10.1.0.22='6417880425364517165'>, (-4006140687792135587L, -4006140687792135586L), set(['zs_logging', 'OpsCenter'])) timed out after 3600 seconds. 2014-06-03 22:16:44-0400 [zs_prod] ERROR: More than 100 errors during repair service, shutting down repair service 2014-06-03 22:16:44-0400 [zs_prod] INFO: Stopping repair service [...] From /var/log/opscenter/repair_service/zs_prod.log: [...] 2014-06-03 22:16:44-0400 [zs_prod] ERROR: Repair task (<Node 10.1.0.22='6417880425364517165'>, (-4006140687792135587L, -4006140687792135586L), set(['zs_logging', 'OpsCenter'])) timed out after 3600 seconds. 2014-06-03 22:16:44-0400 [zs_prod] ERROR: Task (<Node 10.1.0.22='6417880425364517165'>, (-4006140687792135587L, -4006140687792135586L), set(['zs_logging', 'OpsCenter'])) has failed 1 times. 2014-06-03 22:16:44-0400 [zs_prod] ERROR: 101 errors have ocurred out of 100 allowed. 2014-06-03 22:16:44-0400 [zs_prod] ERROR: More than 100 errors during repair service, shutting down repair service 2014-06-03 22:16:44-0400 [zs_prod] INFO: Stopping repair service On the nodes on which the repair fails, from /var/log/cassandra/system.log: ERROR [RMI TCP Connection(93502)-10.1.0.22] 2014-06-03 20:12:28,858 StorageService.java (line 2560) Repair session failed: java.lang.IllegalArgumentException: Requested range intersects a local range but is not fully contained in one; this would lead to i mprecise repair at org.apache.cassandra.service.ActiveRepairService.getNeighbors(ActiveRepairService.java:164) at org.apache.cassandra.repair.RepairSession.<init>(RepairSession.java:128) at org.apache.cassandra.repair.RepairSession.<init>(RepairSession.java:117) at org.apache.cassandra.service.ActiveRepairService.submitRepairSession(ActiveRepairService.java:97) at org.apache.cassandra.service.StorageService.forceKeyspaceRepair(StorageService.java:2620) at org.apache.cassandra.service.StorageService$5.runMayThrow(StorageService.java:2556) at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28) These errors, which only occurs if the repair service is running, are the only errors these nodes experience. Outside of the repair task, the Cassandra cluster works perfectly. I am running Opscenter 4.1.2 with a 6 nodes DSE 4.0.2 cluster installed on linux virtual machines. The nodes run a vanilla installation of Ubuntu Server 12.04 64-bit and DSE was installed and secured according to the provided installation documentation. I have been experiencing that problem on my development cluster for a while too (with DSE 4.0.0, 4.0.1 and 4.0.2), but I thought this was because of some configuration error on my part. The problem has appeared spontaneously at some point too. The Cassandra cluster has been working very smoothly with a good write throughput. It is very stable and has enough resources to work with. We did not notice any problems with the applications that depend on it.

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  • Thrift,.NET,Cassandra - Is this is right combination?

    - by Vadi
    I've been evaluating technology stack for developing a social network based application. Below are the stack I think could well suitable for this application type of application: GUI -- ASP.NET MVC, Flash (Flex) Business Services -- Thrift based services One of the advantage of using Thrift is to solve scaling problems that will come in future when the user base increases rapidly. All the business logic can be exposed as a services using REST,JSON etc., This also allows us to go with C++ or Erlang based services when situation demands. Database -- mySQL, CasSandara mySQL can be used for storing the data which needs to be persisted. Cassandara will be used for storing global identifiers to the persisted data. Since Cassandara is also very good at scaling by introducing more nodes this will leverage Thrift based services as well. And also there is native support between Cassandara and Thrift Cache Server -- Memcached Any requests from Business Services will only talk to Memcached if any non-dirty data is required, otherwise there will be some background jobs that will invalidate the cache from database. The question is: Is the Thrift which is open-sourced one is production-ready? Is it the right stack for services layer to choose when the application (GUI) is primarily gets developed in ASP.NET and DB is mysql? Is there any other caveats that anyone here experienced? One of the main objective behind this stack is to easily scale up with more nodes and also this helps us to use Linux boxes, it will reduce our cost significantly Thoughts please ..

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  • php SimpleCassie Cassandra TimeUUID

    - by chnet
    I created a column family Users using following command: create column family Users with comparator=TimeUUIDType and default_validation_class=UTF8Type; Then I insert a column into Users. It shows as follows. RowKey: jsmith =>(column=66829930-515b-11e0-8443-0f82b246fa40, value=hello, timestamp=1300451382) I want to access it using SimpleCassie. The command is: $data = $cassie->keyspace('Keyspace1')->cf('Users')->key('jsmith')->column('66829930-515b-11e0-8443-0f82b246fa40')->value(); (I also tried: $data = $cassie->keyspace('Keyspace1')->cf('Users')->key('jsmith')->column($cassie->uuid('66829930-515b-11e0-8443-0f82b246fa40')->__toString())->value();) However, They do not work. It always return NULL. How can I get the column value (hello) I want?

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  • cassandra thrift: append data

    - by urssujith
    If I need to append data (not insert) into a particular super column, what should I do? For eg: Consider a existing record described below Kespace : test columFamily: testColum SuperColumn : testSuper column_name : email value : [email protected] Here if I want to add my phone number to the super column "testSuper". What should I do?

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  • how to use timeuuid names in cassandra

    - by Marcin
    Hi guys, I have a problem, I would like to build logging system which will be using timeuuid type as a column name which will allow me ask for it later. Since for range queries order by time I need to use timeuuid type I would like to ask you how can I specify range queries for timeuuid column names if timeuuid is every time unique and I don't realy know the column name because of that I just know the time when it has been stored ? please help

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  • Cassandra performance slow down with counter column

    - by tubcvt
    I have a cluster (4 node ) and a node have 16 core and 24 gb ram: 192.168.23.114 datacenter1 rack1 Up Normal 44.48 GB 25.00% 192.168.23.115 datacenter1 rack1 Up Normal 44.51 GB 25.00% 192.168.23.116 datacenter1 rack1 Up Normal 44.51 GB 25.00% 192.168.23.117 datacenter1 rack1 Up Normal 44.51 GB 25.00% We use about 10 column family (counter column) to make some system statistic report. Problem on here is that When i set replication_factor of this keyspace from 1 to 2 (contain 10 counter column family ), all cpu of node increase from 10% ( when use replication factor=1) to --- 90%. :( :( who can help me work around that :( . why counter column consume too much cpu time :(. thanks all

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  • Is Cassandra database row size limited by available memory?

    - by Adam Hollidge
    I'm working with very long time series -- hundreds of millions of data points in one series -- and am considering Cassandra as a data store. In this question, one of the Cassandra committers (the über helpful jbellis) says that Cassandra rows can be very large, and that column slicing operations are faster than row slices, hence my question: Is the row size still limited by available memory?

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  • Can Tornado communicate with Cassandra, in Non-blocking asynchronous style?

    - by takaomag
    I'm working on a web project, which have to process so many client requests. So I am considering to use Cassandra and tornado. Tornado seems to have a build-in client(tornado.httpclient.AsyncHTTPClient), which can do http Non-Blocking request. But, Cassandra uses Thrift protocol. Using Thrift, Tornado seems to be blocked while quering to Cassandra. Has anyone got expereince? Please suggest how should I do. Or, is there any add-on module for this purpose? Thanks.

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  • Storing and Retrieving TimeUUIDType types with Net::Cassandra::Easy ?

    - by Holden Robbins
    Doing the following: my $c = Net::Cassandra::Easy-new(server = 'localhost', port = '9160', keyspace = 'Keyspace1'); $c-connect(); my $uuid_bin = Data::UUID-new()-create_bin(); eval { $result = $c-mutate([$key], family = 'StandardByUUID1', insertions = { $uuid_bin = '123' }); }; warn $@ if $@; Result is a: Net::GenCassandra::InvalidRequestException I didn't see anything similar to Net::Cassandra::Easy::pack_decimal for UUIDs.

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  • How to get properties from Cassandra with get_slice in Erlang?

    - by Zubair
    I am using Erlang to interface with Cassandra and I cannot get the get_slice command to return a list of all the columns of a row. I use: X = thrift_client:call( C, 'get_slice', [ "Keyspace1", K, #columnParent{column_family="KeyValue"}, #slicePredicate{}, 1 ] ), : but I get back : invalidRequestException,<<"predicate column_names and slice_range may not both be null">> : However, using the cassandra-cli interface this works fine. Any ideas?

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  • Which Cassandra API provides the highest level of abstraction?

    - by knorv
    There are a lot of Cassandra API:s available and usually the programming language preference determines the choice of API. However, if we take the programming language component out of the equation, what Cassandra API provides the highest level of abstraction? Definition of "level of abstraction" in this context: An API providing a lot of extra goodies such as index handling, etc would be considered being at a higher abstraction layer than a bare bones "close to Thrift" API.

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  • Learn a NoSQL or become a badass with traditional RDMS - Where is/will the work be?

    - by beck
    I'm half way through my MSc and am thinking about my dissertation which I get 3 months to work on full time. Im very comfortable with the traditional Relational Database, the question is should I work on a project where I get a good understanding of something like Cassandra, or should I really push my RDMS knowledge to the limit. Getting great at something like MySQL is a solid safe option, will there really be much work for me with Cassandra in my tool belt? I would love to do either.... Thanks for your opinions and advice.

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  • How do I store and retrieve TimeUUIDType types with Net::Cassandra::Easy?

    - by Holden Robbins
    Doing the following: my $c = Net::Cassandra::Easy->new(server => 'localhost', port => '9160', keyspace => 'Keyspace1'); $c->connect(); my $uuid_bin = Data::UUID->new()->create_bin(); eval { $result = $c->mutate([$key], family => 'StandardByUUID1', insertions => { $uuid_bin => '123' }); }; warn $@ if $@; Result is a: Net::GenCassandra::InvalidRequestException I didn't see anything similar to Net::Cassandra::Easy::pack_decimal for UUIDs.

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  • What in-client caching options work well with Cassandra and Java?

    - by sanity
    I'm currently architecting a system that must be capable of dealing with tens of thousands of writes per second. I am more-or-less settled on using Apache Cassandra for the persistence layer, and will be using Java for the application layer, but there are situations where I need to quickly access data in a way that picks up any changes within seconds. Hitting Cassandra every single time I need to check this data for changes will be too slow, which means I need to use some kind of application layer caching. To ensure that the cached data remains current, ideally it would support some kind of multicast-based cache invalidation. What are my options?

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  • Building a News-feed that comprises posts "created by user's connections" && "on the topics user is following"

    - by aklin81
    I am working on a project of Questions & Answers website that allows a user to follow questions on certain topics from his network. A user's news-feed wall comprises of only those questions that have been posted by his connections and tagged on the topics that he is following(his expertise topics). I am confused what database's datamodel would be most fitting for such an application. The project needs to consider the future provisions for scalability and high performance issues. I have been looking at Cassandra and MySQL solutions as of now. After my study of Cassandra I realized that Simple news-feed design that shows all the posts from network would be easy to design using Cassandra by executing fast writes to all followers of a user about the post from user. But for my kind of application where there is an additional filter of 'followed topics', (ie, the user receives posts "created by his network" && "on topics user is following"), I could not convince myself with a good schema design in Cassandra. I hope if I missed something because of my short understanding of cassandra, perhaps, can you please help me out with your suggestions of how this news-feed could be implemented in Cassandra ? Looking for a great project with Cassandra ! Edit: There are going to be maximum 5 tags allowed for tagging the question (ie, max 5 topics can be tagged on a question).

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  • MongoDB vs. Redis vs. Cassandra for a fast-write, temporary row storage solution

    - by Mark Bao
    Hi there, I'm building a system that tracks and verifies ad impressions and clicks. This means that there are a lot of insert commands (about 90/second average, peaking at 250) and some read operations, but the focus is on performance and making it blazing-fast. The system is currently on MongoDB, but I've been introduced to Cassandra and Redis since then. Would it be a good idea to go to one of these two solutions, rather than stay on MongoDB? Why or why not? Thank you

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  • Get Started with .Net and Apache Cassandra

    - by Sazzad Hossain
    Just came across a easy and nice to read article explaining how to get started with noSQL database system. These no relational databases are getting increasingly popular to tackle the distribution and large data set problems.Cassandra's ColumnFamily data model offers the convenience of column indexes with the performance of log-structured updates, strong support for materialized views, and powerful built-in caching.The article is nicely written by Kellabyte  and shows step by step process how to get going with the programming in a .net platform.Read more here.

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