Questions tagged [cassandra]

Apache Cassandra is an open source distributed database management system. It is designed to handle very large amounts of data spread out across many commodity servers while providing a highly available service with no single point of failure. It is a NoSQL solution.

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How to choose database for scalable chat systems? [closed]

I have made a chat application where for now I am storing complete history of chat of all the users. I am using django as backend and postgres as the database. I am nearing 100k daily active users ...
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Cassandra multi data centre cluster configuration [closed]

We are decided to use "cassandra" as a database and now want to go with cluster with two datacenters DC1 & DC2. This DC2 is for backup purpose and it is replica of DC1. Initially we are expecting ...
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Can Cassandra prevent TTL from updating on upsert of table

I have a Cassandra table that is like this... CREATE TABLE IF NOT EXISTS analytics.data( id double, data text, PRIMARY KEY(id, data) ) WITH default_time_to_live = 120 AND gc_grace_seconds ...
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What is the best compaction strategy for overwritable/mutable/upsert-able data?

Suppose I have a Cassandra table like this: CREATE TABLE keyspace.last_modified ( category text, subcategory text, id text, created_at bigint, PRIMARY KEY ((category, subcategory, ...
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20 views

Stopping N number of nodes of a Cassandra cluster running on a single machine using bash script

I have set up a Multi-Node cassandra (3.11) cluster (with N nodes) in a single Ubuntu machine. I have written a bash script which Creates N copies of conf folder Configures the cassandra yaml file ...
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219 views

Copy/move data from one cassandra server to another

I'm in the midst of replacing a kubernetes stack (to more specific: moving it from a locally hosted cluster to an AKS cluster in Azure), and as a result have to re-create all of my services, including ...
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Allocate space in Cassandra

We run a Cassandra cluster with 2 DC, 3 nodes each (2 RF). The state of the cluster is quite bad (never repaired) and the disks were getting full so we added additional nodes which after the bootstrap ...
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27 views

User Grant in cassandra DB

I would like a user abc to access only a single keyspace and no other keyspaces in the Database. How can I achieve so?
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Why getting Error accessing Cassandra with DataStax ODBC Driver?

We are using Cassandra 2.2.11, and trying to configure DataStax ODBC driver. We are getting the following error message: SQLSTATE: HY000[DataStax][CassandraODBC] (10) Error while executing a query ...
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8 views

Show cassandra help documentation in terminal instead of browser

I've just started playing around with Cassandra through the cqlsh cli. When using the help command for the topics the documentation opens in the browser. Is there a way to show the documentation in ...
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77 views

Does Cassandra CQL provide a command to generate an execution plan?

In Oracle and other DBs you can generate an execution plan for SQL. Is this possible for Cassandra? I want to determine if it is possible to measure the relative complexity of several CQL statements ...
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326 views

Cassandra querying without full primary key

As far as I understand there are no secondary indices with multiple columns, only single columns. So how do I solve the index problem I'm having? This is my table: CREATE TABLE IF NOT EXISTS logstv....
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Cassandra pool warning displaying continuously

I am using the Cassandra driver for python in Spyder. I am trying to fetch some data from Cassandra table. Here is my code: from cassandra.cluster import Cluster cluster=Cluster(['some_ip']) session=...
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24 views

Is there a way to change the compaction throughput via startup options in Cassandra?

We are currently running a Cassandra cluster in K8S containers as Stateful sets. We're considering exposing the config file but we would like to know if perhaps we can provide this value as a startup ...
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1answer
74 views

Apache Cassandra INSERT-only permissions

Looking at the Cassandra documentation, it appears that the smallest write-only permission on a table you can grant is MODIFY, which includes UPDATE, DELETE and TRUNCATE. Is there a proper way to ...
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20 views

cassandra nodes have diff value

I have 3 node cluster, problem is that for some rows , updatetime column have different value on 3 node: like : 1st node : updated_on | 2018-08-22 17:01:30+0530 2nd node : updated_on ...
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185 views

Error on cassandra-3.11.3-1.noarch centos7

I've a cluster consisting of 5 cassandra nodes. The cassandra version used is cassandra-3.11.3-1.noarch The keyspace strategy and is defined as follows: CREATE KEYSPACE my_keyspace WITH ...
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202 views

How to deal with unbounded growth in cassandra shards

Let's say we have a website like youtube where we have a comment session per e video. Users want to be able to comment and to see the comments made by other users by comment creation time. This is ...
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28 views

Data replication in Cassandra

We have a 5 node cluster in Cassandra in which we have created a keyspace with RF=3. After creating a column-family(table) when we insert the data into the same, it is getting replicated in all the ...
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Kill client connection to Cassandra instance

Not able to go to find any documentation on how to kill a client connection to remote Cassandra I will instance .. as a DBA at the server end? Seems like an easy task but why no mention of this in ...
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387 views

Python version issue on Cassandra 3.11.2

Searching around I found a lot of thread about this problem (coming from 2012) but I can't find an official solution: running cqlsh.bat File "C:\apache-cassandra-3.11.2\bin\\cqlsh.py", line 146 ...
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177 views

Cassandra multi-DC:write on LOCAL and read from any DC

We use a multi-data center (DC) cassandra cluster. During write on to the cluster, I want only LOCAL DC to perform writes on its nodes as we are already routing the write requests to the desired DC ...
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OpsCenter missing in Datastax Cassandra for Windows

Following this guide within the Cassandra installer I should get OpsCenter too. But this screenshot https://www.datastax.com/wp-content/uploads/2012/01/dsc-win4.jpg doesn't match the current release (...
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39 views

Cassandra Cluster storage

I want to try out Cassandra Cluster. My main question is about scalability. Every node in a Cassandra cluster has the same copy of data. So when I have in total 1 TB and have 5 nodes -> 5TB. This at ...
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22 views

SQL Join vs NoSQL Wide column

If we need to have 2 tables, one storing the author info(author_info), & another storing all the books info(book_info). author_info has authorId as it's primary key, whereas the book_info table ...
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37 views

Hints gc_grace and expirations

Have 3 node cluster. RF=3. Table with gc_grace_seconds = 120 secs. max_hints duration as default at 3 hours. inserted a row nodetool flush on all the 3 nodes bring down node 3 delete the inserted ...
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602 views

dropping a table does not delete the directories on the disk

I am just testing the drop table command in Cassandra 3.11. The sequence is as follows: Load data worth 10gb drop the table on the node, nodetool flush nodetool clearsnapshot nodetool cleanup ...
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How these conflicting scenarios will work in cassandra when one of the mode crashes?

Say we have two nodes(simple replica no sharding) i.e. N1,N2 with replication factor as 2. I am using default Read and write consistency levels i.e. R and W are 1 which means it will read/write from/...
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161 views

Handling read conflict in cassandra?

Say we have three nodes(simple replica no sharding) i.e. N1,N2 and N3 with replication factor as 3. As read and write request can go to any node, Say Request write request(to update the same ...
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46 views

Replica model in Cassandra vs Mongo?

Say in Mongo we have one primary and two replica node(simple replica no sharding). Read and write request will be handled only primary node and replica will just backup the data in case of failover. ...
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666 views

Mongo CP, Cassandra AP?

I have read lot of articles on net but still confused why Mongo CP, Cassandra AP, RDBMS CA ? Will explain my understanding and query along with that . Mongo Consider a scenario where I have ...
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49 views

best way to retrieve data using multiple parameters in Cassandra?

I have created a table that contains the userid, the content that they posted on their newsfeed, the date of when they posted it, and a primary key(I am using nodejs) my first shot at retrieving the ...
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Cassandra - High Number of Dropped Mutations (Specific Table on a specific Node in the cluster)

History Leading to this issue: My Compression strategy in Production was LZ4 Compression. But I modified it to Deflate For compression change, we had to use nodetool Upgradesstables to forcefully ...
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What things we should consider when configuring Cassandra Cluster?

I'm new to Cassandra, so wanted to understand what basic things we should consider when are we going to configure Cassandra cluster in on or multiple database centers? Thanks!
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504 views

Cassandra writing (too?) large partitions

I have a Cassandra cluster running for quite some time now (months) and, as expected, it has been consuming large quantities of data every day. In the past few days the cluster has been having ...
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36 views

Cassandra - reinserting a node

I had to remove a cassandra dead node on a hurry (because an important script with a truncate query wouldn't work due to consistency level reasons -- any thoughts on that would be nice too). Anyway, ...
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152 views

Cassandra nodes are not equal

We have two nodes. Node1 was down for a long time. During this time Node2 raised 1 TB capacity when Node1 has 100 GB. We tried to repair Node1 with nodetool repair but nothing changed. After that we ...
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49 views

Can I use result of one query inside other query in Cassandra

I need to delete all rows with given clustering column value. I don't have partition key so I don't have complete primary key. To delete record from Cassandra table we need to provide specific ...
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151 views

user based trace enable in Cassandra

i have created user and role in Cassandra and tracing is enabled. but sessions and event table does not capture user info. below tables gives information about what query has been executed and from ...
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password expire duration and maximum invalid login attempts

how to set password expire duration and maximum invalid login attempts for user under Cassandra DB ? for example user test tried to login with incorrect password 5 times , that should should get ...
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Is Cassandra's manual node addition/removal tasks tedious and practical in a large cluster?

I am evaluating using Cassandra as a large key-value store over about 500 commodity machines. AFAIK, Cassandra requires manual intervention during permanent machine failures (removing the deadnode, ...
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324 views

How to get information about the current cluster configurations with list of datacenters?

Is any way to get information about the current cluster configurations with a list of datacenters? I have tried to fetch this list from system.local using cqlsh with setting the consistency level ...
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571 views

Database latency vs throughput

I'm a bit confused by terms latency and throughput in case of databases. My understanding is that latency represents time needed to perform a single request (e.g. insert or select), while the ...
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1answer
111 views

How far does one table, one query go?

I'm doing a MySQL to Cassandra conversion. The fundamentals of the dataset are a master table of size ~10^7 rows to which several subsidiary tables are linked by foreign key. The subsidiary tables are ...
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50 views

Cassandra cluster configuration

I have a cluster of 4 nodes in a data center dc1 Rack1. Now I have to create data center dc2 into same cluster. Will I need to reconfigure whole cluster or is there any way?
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758 views

Why doesn't nodetool work on my Cassandra Cluster?

I have never been able to get nodetool to operate correctly to give me information about my cluster. We have a simple 3-node cluster of Cassandra 3.11.1 nodes running under CentOS 7.3 -- using the ...
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2answers
4k views

how to import a huge csv file into Cassandra?

I am trying to import a csv file into Cassandra which is very long. These are food products: ingredients, nutrition, labels... It comes from Open Food Data. List information on food products: ...
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282 views

List Roles on cassandra getting NoHostAvailable on one DataCentre

I have a 2 DC cluster, 'main' and 'bi' with a replication factor of 3 and a NetworkTopologyStrategy. When I call LIST HOSTS; in cqlsh, my bi datacentre lists all the roles appropriately, but I get a ...
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298 views

Quorum read consistency in Cassandra

I'm new to distributed databases and there are a couple of things I couldn't figure out. We're developing an application and need to select the right database, this application needs strong ...
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767 views

Unable to get Cassandra in a Docker to talk to cluster

Trying to get Cassandra running in a docker using the official docker image. When I execute the below lines of code it starts then stops the docker without connecting to the cluster. I have checked ...