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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75
votes
5answers
35k views

Which database could handle storage of billions/trillions of records?

We are looking at developing a tool to capture and analyze netflow data, of which we gather tremendous amounts of. Each day we capture about ~1.4 billion flow records which would look like this in ...
16
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5answers
4k views

Infrastructure for Highly Concurrent, High Write DB

My requirements are: 3000 Connections 70-85% Write vs Read Currently, we are maxing out a High-CPU, Extra Large Instance at 700 connections. All 8 cores are maxed. We think it's the number of ...
15
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1answer
525 views

Is it safe to add a new node to a Cassandra cluster while a repair is running?

I'm getting ready to expand an existing Cassandra cluster. I have repairs scheduled to run on a reoccurring basis. Do I need to disable repairs when adding a new node to a cluster, or can I ...
13
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1answer
454 views

Cassandra multidatacenter configuration with 1 external ip

I'm trying to setup a multi-datacenter Cassandra cluster. The problem is that my datacenters have only 1 external IP (wan IP), I can setup port forwarding on the data centers switchs to access each ...
12
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3answers
14k views

Do you have to run nodetool repair on every node?

Do you have to run nodetool repair on every node in a cluster, or do you only need to run it on one node, and from there Cassandra will take care of the rest?
11
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2answers
24k views

What is a good way to copy data from one Cassandra ColumnFamily to another on the same Keyspace (like SQL's INSERT INTO)?

Trying to find a way to easily transfer all the rows from a Cassandra ColumnFamily/Table to another. The COPY command, as I understand, is a good option. However, as it dumps all the data to .csv on ...
11
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2answers
3k views

What are the penalties of using many (thousands) of column families or keyspaces in Cassandra?

I am in the process of evaluating the best design for our Cassandra installation. There is not so much information out there on the Internet about using the first two levels of access that Cassandra ...
10
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1answer
5k views

What are the practical limitations on a column family in Cassandra?

In Cassandra, it's not recommended to have more than a few thousand column families, let's say 2,000 for the sake of argument. In cases where more than 2,000 types of data need to be persisted, one ...
9
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2answers
6k views

Cassandra: maintenance

I am inexperienced with Cassandra, but I have some experience with SQL-based relational databases. I have been unable to find best practices information about how to maintain Cassandra once deployed. ...
9
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2answers
4k views

Why does Cassandra recommend against creating an index on high-cardinality columns?

The Cassandra documentation states, Do not use an index in these situations: On high-cardinality columns because you then query a huge volume of records for a small number of results. See ...
9
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2answers
2k views

NoSQL : What is unstructured data?

we are currently running at the edge of resources with our mssql server based solution. We have now many traditional options regarding the next move to tackle the load: buy faster CPUs and IO split ...
8
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3answers
6k views

“phpMyAdmin” for Cassandra

Is there a tool like phpMyAdmin for RDBMS-MySQL for a Cassandra DB? I know that there is less "runtime" config possible (column families can not be edited at runtime etc.). Nevertheless, it would be ...
7
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2answers
29k views

Cassandra - Query a column with collection type

I am pretty new to cassandra, so pardon me if this turns out to be a silly question. I have a table structure as below CREATE TABLE data_points ( id text PRIMARY KEY, created_at timestamp, ...
7
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1answer
6k views

Querying Cassandra without a partition key

I read Cassandra's documentation on the internal steps it performs when querying data. It looks like Cassandra relies on the Partitioner and Replication Strategy to process queries. I am still ...
7
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1answer
6k views

Modeling Graph Data in Cassandra DB

I want to use Apache Cassandra to store a large amount of graph data according to a property graph model. The model contains the following entities: Vertices: Contains a map of key/value pairs (...
6
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1answer
5k views

Cassandra one-to-many table design

I am new to Cassandra from 20 years of RDBMS, and over the last few days have been reading and watching everything I can get my hands on that applies to my situation. I'm sure this is a basic ...
6
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2answers
5k views

Migration from Cassandra 2.x to 3.x: schema_keyspaces table is gone. How do you query system keyspaces?

I just migrated from Cassandra 2.x to 3.x (specifically, 3.4). Now the system tables have completely changed, and these changes are not in the documentation. If you look at the current CQL docs for ...
5
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1answer
7k views

Querying from system.schema_keyspaces generates code=2200 [Invalid query]

I'm following Cassandra docs to learn CQL but when I type the query SELECT * from system.schema_keyspaces; the system generates InvalidRequest: code=2200 [Invalid query] message= unconfigured table ...
5
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2answers
869 views

Cassandra cluster monitoring

We using Nagios for our servers monitoring. Each web-environment have 1 cluster as backend - Cassanra 2.0. Each cluster have 3-5 nodes. Question is: I want write a plugin for Nagios, for Cassandra's ...
5
votes
1answer
3k views

ALLOW FILTERING vs NOT; Cassandra Data Model Question

I have a toy Cassandra cluster running on some RaspberryPis at home. I am currently logging CryptoCoin data to it in hopes of learning more about Cassandra and as well as some other things along the ...
5
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2answers
18k views

Is there any open source GUI tool to monitor cassandra? [closed]

I would like to monitor cassandra database as well as need to check the values in the database. Could any one suggest me best open source GUI tool ? Regards, Arun Raj.
5
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2answers
3k views

How can a Cassandra node see another node as down?

I'm running Cassandra on three nodes. Here's their nodetool status output: ubuntu@ip-10-0-8-8:~$ nodetool status Datacenter: us-east =================== Status=Up/Down |/ State=Normal/Leaving/Joining/...
5
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2answers
5k views

Cassandra encryption at rest

I need to store some sensitive data in Cassandra and require it to be encrypted at rest. Is it likely Cassandra would function normally on top of a Linux encrypted file system (something like the open ...
5
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1answer
4k views

Cassandra “Operation timed out - received only 0 responses.” during write

I'm using Datastax PHP Cassandra Driver and Cassandra 2.2.5 on Windows 10. This is a single-node cluster, and the keyspace replication of { 'class': 'SimpleStrategy', 'replication_factor': 1 }...
5
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1answer
78 views

Cassandra alters

I have cassandra table defined as: CREATE TABLE db.table ( value text, time timestamp, sid text, PRIMARY KEY (sid, time) ) WITH CLUSTERING ORDER BY (time ASC) AND ...
4
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2answers
314 views

Which database system can break me free?

I am currently running a MySQL Database for logging and analyzing those logs. My current table schema looks like this: CREATE TABLE `mylogs` ( `transfer_id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT ...
4
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1answer
6k views

How can I get nodetool without Cassandra

I have Cassandra pool across machines in LAN. I need nodetool on machine without Cassandra installed. How can I get it? Is the installing Cassandra and disabling db service is the best way?
4
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1answer
1k views

Cassandra - Why does Read/Write Latency fluctuate?

Question Why does write (read as well) latency fluctuate in Cassandra? Background Running Cassandra Stress Tool on a node (s01) against another node (m01). Run several times but always saw the ...
4
votes
1answer
2k views

Filter rows, but only select most recent row for each Id

I have some code that is processing a lot of tasks. These tasks are either connected to a user or an account. Each Task go through many statuses -> Queued, Started, Error, Postponed, Queued, Started, ...
4
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0answers
285 views

Why I get Cannot achieve consistency level ONE (Code 4096)? [duplicate]

Why I write to table, I get error: Cannot achieve consistency level ONE (Code 4096) What could be wrong? Here is my descriptions: DESCRIBE schools CREATE KEYSPACE schools WITH replication = {'...
3
votes
1answer
6k views

Why I got NoHostAvailable:?

if I run this simple query: SELECT * from myapp.latests WHERE organization_id = 1 and user_id = 1; I get error: NoHostAvailable: Running nodetool status results into: Datacenter: eu-central ======...
3
votes
1answer
577 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 ...
3
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1answer
354 views

Optimal database for large number of columns or rows

Problem 1: I have one file with 567 rows and 16,382 columns, most of which are floating point numbers. I have another file with 117,493 rows but only 3 columns. The contents deal with biology and ...
3
votes
1answer
67 views

Can Cassandra be used to increase database write rate?

I am developing a database for an analysis job that requires parsing terabytes of information into a database. My job is to create and populate a database and using it to answer analyst's questions. ...
3
votes
1answer
555 views

Each node holds 50% of data on 2 nodes with replication_factor=1

Description: Linux OS, Cassandra 3.9, Using CCM to create 2 Nodes, Consistent Level = One replication = {'class': 'SimpleStrategy', 'replication_factor': '1'} Using writing script (* ) as below (...
3
votes
1answer
818 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 ...
3
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1answer
2k views

How does the Cassandra distribute data?

I cannot find a detailed document on this anywhere, however, that being said, if anyone has an answer to my question, I would be extremely grateful. In regards to Cassandra's standard node ...
3
votes
1answer
2k views

Upgrading Cassandra from 1.1.0 to latest

I have a single node cassandra database running since 2 years now... never had any issues with it, but I would like to upgrade it to the latest cassandra (2.1.2 at the time I write those lines), of ...
3
votes
2answers
655 views

Help in understanding Hinted Handoffs and Data replication in Cassandra

We have a 3 node Cassandra cluster with RF = 2. The read and write consistency is set to ONE. We are using Vnodes as well. Lets label these nodes as N1, N2 and N3. Let's say that N3 goes down. I was ...
3
votes
1answer
16k views

Cassandra row ordering best practice

I have a column family that store articles. I'll need to get those articles from the most recent to the oldest, getting them from Country, and of course the ability to limit the number of fetched ...
3
votes
1answer
812 views

Keeping rows ordered by counter value

I'm storing linked words in a Cassandra v2 cluster and I'm having a hard time doing efficient reads. I'm trying to fetch the top X rows with the highest counter value. Cassandra doesn't store the ...
3
votes
0answers
51 views

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 ...
3
votes
0answers
149 views

Securing a Cassandra Cluster

We've managed to set up a Cassandra 2.2.6 cluster of two physical nodes (nodetool sees both of them, so I'm quite certain the cluster is indeed active). My steps to create the cluster were (this ...
3
votes
0answers
260 views

Is it good practice to have multiple keyspaces in Cassandra?

I've Cassandra configured on Amazon EC2 having 3 nodes(instances) in single cluster. Now what I want to do is give some space on Cassandra to my clients by creating separate keyspace for each in a ...
2
votes
1answer
2k views

Cassendra schema design suggestion for chat archive

I have gone though this article and here is the schema I have got from it. This is helpful for my application for maintaining statuses of a user, but how can extend this to maintain one to one chat ...
2
votes
1answer
31 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 ...
2
votes
1answer
835 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 ...
2
votes
2answers
34 views

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, ...
2
votes
1answer
528 views

Cassandra backup from all nodes or just one?

Cassandra is a distributed database, where each node is in sync with the other nodes from the same ring/cluster. When taking backups based on a snapshot, do I need to back up each node individually ...
2
votes
1answer
2k views

Cassandra nodetool repair scheduling and gc_grace_period

I am trying to devise a scheme with minimal repair frequency to not overload the system, and have a problem to understand how can I ensure that the data is not getting resurrected. I have a cassandra ...