by   DanoshiFusermoto Java Version: Current License: No License

kandi X-RAY | cassandra Summary

kandi X-RAY | cassandra Summary

cassandra is a Java library typically used in Big Data applications. cassandra has no bugs and it has low support. However cassandra has 3 vulnerabilities and it build file is not available. You can download it from GitHub.


            kandi-support Support

              cassandra has a low active ecosystem.
              It has 12 star(s) with 0 fork(s). There are 4 watchers for this library.
              It had no major release in the last 6 months.
              There are 3 open issues and 0 have been closed. There are no pull requests.
              It has a neutral sentiment in the developer community.
              The latest version of cassandra is current.

            kandi-Quality Quality

              cassandra has no bugs reported.

            kandi-Security Security

              cassandra has 3 vulnerability issues reported (0 critical, 2 high, 1 medium, 0 low).

            kandi-License License

              cassandra does not have a standard license declared.
              Check the repository for any license declaration and review the terms closely.
              Without a license, all rights are reserved, and you cannot use the library in your applications.

            kandi-Reuse Reuse

              cassandra releases are not available. You will need to build from source code and install.
              cassandra has no build file. You will be need to create the build yourself to build the component from source.

            Top functions reviewed by kandi - BETA

            kandi has reviewed cassandra and discovered the below as its top functions. This is intended to give you an instant insight into cassandra implemented functionality, and help decide if they suit your requirements.
            • Builds a pending block
            • Store a block
            • Gets a list of PendingAtoms
            • Gets an object from the database
            • Main entry point
            • Returns the balance of a given token
            • Retrieves the list of token particles for a given quantity
            • Checks whether peer is synced
            • Region provisioning
            • Disconnect peers
            • Process pending branches
            • Run the command
            • Creates a new ObjectMapper for serialized DTO
            • Start serving requests
            • Removes pending atom
            • Entry point for the spammer
            • Executes this transfer
            • Returns a pending atom or null if there is no pending atom
            • Request items from a peer
            • Constructs a raw NTP packet
            • Initializes the state machine
            • Execute the network
            • Parses and prints messages
            • Commit atoms on the given branch
            • Entry point for the program
            • Commits a pending block
            Get all kandi verified functions for this library.

            cassandra Key Features

            No Key Features are available at this moment for cassandra.

            cassandra Examples and Code Snippets

            No Code Snippets are available at this moment for cassandra.

            Community Discussions


            cassnadra multi/single partition batch explanation
            Asked 2021-Jun-14 at 12:46

            I red the cassandra docs about Good use of BATCH statement - single partition batch example I want to understand about multi/single partition batch.

            According to the docs this is a single partition batch.



            Answered 2021-Jun-14 at 12:41

            First partition is - 'Vera ADRIAN', 2 Second partition - 'Vera ADRIAN', 3

            Could u explain pls why is it single partition batch?

            Sure. Because the expense_id is not part of the partition key. Therefore, Vera ADRIAN is the same partition key value used in both INSERTs.

            For the 2nd part of your question, you're right in that the 2nd example does not appear to be a multi-partition query as the cart_ids are the same. Following your link above, I quickly found a bad use of BATCH (multi-partition):



            Initializing a list by a value from another column
            Asked 2021-Jun-14 at 05:55

            I have a table in Cassandra DB, with some columns, for example:



            Answered 2021-Jun-14 at 05:51

            No, it’s not possible to do only with CQL - you need to have some code or tool to do that - it should scan the whole database, read the data and put them into destination column. Besides trying to write your own code, that it’s usually hard to write correctly you can use:

            • DSBulk - you can unload data into CSV or JSON file, convert the data into specific representation by using sed or something like, and load data into the new column. But transformation step is something that you will need to implement, and it could be hard to debug if you have data with quotes, etc.
            • Spark + Spark Cassandra Connector (even in the local mode) - although it's still a piece of code, it would be easier to implement from my point of view. Just start pyspark with options specified in the documentation, read data from Cassandra, transform, and store them back into Cassandra. Something like this (not tested):



            cassandra 3.11.9 system_auth need to be SimpleStrategy or NetworkTopologyStrategy on production env?
            Asked 2021-Jun-14 at 02:52

            What is the recommended for cassandra (apache) 3.11.9 system_auth? need to be SimpleStrategy or NetworkTopologyStrategy? And with how much RF?

            We have cassandra with 1 dc (2-3 AWS racks with EC2_snitch + dynamic_snitch disabled). Most queries running on consistency level local_one). Today our system_auth keyspace configured SimpleStrategy with RF 3. In a lot of queries, we are wasting time on (tracing):



            Answered 2021-Jun-14 at 02:51

            I answered this question a while ago, which is similar: Replication Factor to use for system_auth

            Due to issues that can happen with larger clusters which fluctuate in size, we now treat system_auth like we do any other keyspace. That is, we set system_auth's RF to 3 in each DC.

            tl;dr;, if you're using NetworkTopologyStrategy on your non-system keyspaces, then you should also be using it for system_auth. Same with your RF; I'd always match the RF of system_auth with that of my "normal" keyspaces, as well.

            No, the replication strategy and RF used on system_auth does not typically cause query latency. That is of course, unless any of the Security cache settings have been altered. 10 years of working with Cassandra, I've never had to change those:

            queries wasting time on (tracing): "Executing single-partition query on roles [ReadStage-X]"

            This statement got me thinking: Are you tracing queries in cqlsh while logged in as the default cassandra user? That user does trigger some cqlsh operations to execute at QUORUM. Could also be that maybe the query consistency and connection consistency are set differently. Just a thought.



            Janus Graph backend cassandra vs Bigtable
            Asked 2021-Jun-10 at 19:37

            I am planning to use Janusgraph for building graph of different uses our team handles and I see that janus graph has option to use BigTable or Cassandra as storage backend. I am looking for any recommendation on which backend is more optimal/performant ( I am mainly talking about gremlin query performance on 2 hop neighbor of a node ) with JanusGraph.

            I understand that performance is pretty subjective and varies based on datasize/graph connectivity and use case so best approach will be to try out myself, which I am planning to do. But has anyone else has done similar performance comparison ? Is there any general recommendation about storage backend here ?



            Answered 2021-Jun-10 at 18:14

            You're right in that performance is both:

            • subjective
            • depends largely on data size

            I can tell you that I have done this exercise as well. To that end, I think it's important to share this comparison from

            In terms of performance, the biggest thing I'd be looking at is how each handles consistency. As a general rule, databases which enforce stronger levels of consistency typically have to sacrifice performance.

            • BigTable == strong-consistent
            • Cassandra == eventually consistent

            Other factors worth considering, are the fact that BigTable limits you to Google Cloud (GCP). And if you don't want to lose performance over the network, you'll also need to pay for more (Janus) instances on GCP for data locality.

            In terms of raw DB-Engine "score," Cassandra is currently at 114.112, while BigTable is at a paltry 3.582. These scores will change month-to-month, but in general this signifies that Cassandra has a much stronger community around it. Similarly, Cassandra has 18182 questions on this site, while BigTable only has 449. Bottom line, is that it'll be much easier to get support and answers to questions.

            Just based on the underlying strength of the community, Cassandra is the better option here.

            Having supported JanusGraph on Cassandra for the last few years, I can tell you that overall it's been solid. The difficulties tend to come into play with bulk data loading. But outside of that, things seem to run pretty well.



            Spring Cassandra time out query 'SELECT * FROM system_schema.tables' timed out after PT2S
            Asked 2021-Jun-10 at 14:20

            I am using Spring Boot 2.4.4 and Spring Data Cassandra dependency to connect to the Cassandra database. During the application startup, I am getting a DriverTimeout error (I am using VPN).

            I have gone through all the Stack Overflow questions similar to this and none of them worked for me. I have cross-posted the same question on the Spring Boot official page here.

            I used below configuration properties below -



            Answered 2021-Apr-23 at 08:35

            The DriverTimeoutException gets thrown when the driver doesn't get a reply from the coordinator node. It uses the basic request timeout default of 2 seconds:



            Spring boot application with spring data cassandra failing to start
            Asked 2021-Jun-10 at 11:33

            I have a spring boot application with spring web & spring data cassandra as dependencies. And I have a main method in a class annotated with @SpringBootApplication.



            Answered 2021-Jan-07 at 22:38

            The problem is the connection with the cassandra. Make sure that you've been created the keyspace-name on cassandra. After that in your project declare a Bean Configuration with the keyspace, in my case mykeyspace. You can visit for more details about setting up the keyspace.



            Cassandra update column should update column value but not the ttl?
            Asked 2021-Jun-10 at 07:16

            I want to know if there is a way to update the column value in cassandra but the column ttl that is present already should remain the same.

            Could you please let me know if this is possible?



            Answered 2021-Jun-10 at 07:16

            You can update the ttl to desired value while updating the column. I mean you can achieve it programatically. Please go through this page ( ) for examples.



            Cassandra data modeling understanding
            Asked 2021-Jun-09 at 19:12

            I came from SQL and switched now to CQL. I don't quite understand something yet.

            In SQL this works:



            Answered 2021-Jun-09 at 14:23

            Cassandra doesn't have joins, so you can't do it - if you need to perform the join, then it should be done in your application.

            Cassandra encourages the data denormalization, when you can copy necessary data into another table to avoid joining when reading data - like, for cart table, you can copy price/description from the product table, and then when displaying the cart you won't need to query the product table.

            I recommend to read first chapters of "Casasndra: The Definitive Guide, 3rd edition" book - it's freely available. This will help you with understanding how to model data for Cassandra



            what do you think about read performance in cassandra?
            Asked 2021-Jun-09 at 12:27

            I read a lot of articles. Many says cassandra is fast in read many says cassandra is slow. I mean a lot of big companies uses cassandras. If it were slow, they dont would use it or i am wrong ?

            Maybe I want to search an Article by id and I have 10 million rows, would it take more than 1-2 seconds ?

            Whats your opinion?



            Answered 2021-Jun-09 at 12:27

            I work with hundreds of companies who use Cassandra on a daily basis and most of these companies do things on internet scale.

            Most of their SLAs require ~6 millisecond read latency 95% of the time at peak app traffic. For that reason, a 2-second latency is a read timeout in Cassandra terms.

            For those who say it is slow, I'll let the tech giants do the talking for Cassandra -- Apple, Netflix, Uber, Visa, FedEx, Sony, GE, Expedia and the list goes on and on and on. :)



            How to copy public ssh-keys to a host using ansible
            Asked 2021-Jun-09 at 05:57

            I have a Cassandra cluster that contains 6 nodes which I already have in an inventory:



            Answered 2021-Jun-09 at 05:53

            You want to use the authorized_key module.

            For example:


            Community Discussions, Code Snippets contain sources that include Stack Exchange Network


            No vulnerabilities reported

            Install cassandra

            You can download it from GitHub.
            You can use cassandra like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the cassandra component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer For Gradle installation, please refer .


            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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