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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Find byte string in Cassandra blob

How doees one find all records in a Cassandra table containing a specified string of bytes within a BLOB field? For example, if I am looking for the byte string 0x56789A, I would want to find it in ...
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Should I use JSON or related tables to represent a relation in Cassandra?

I know it is possible to store JSON in Cassandra, and I also know that Cassandra is a structured query language. Because of these two informations, I am unable to determine whether I should store some ...
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How is data temporary stored while reading in Cassandra

I am trying to create join operation feature inside Cassandra and still trying to understand how data is read in Cassandra. I have read datastax documentation about How is data read in this following ...
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Are there bigtable uses that are anti-patterns? Especially, will doing many writes of the same data (same key) be an issue?

I've been using Cassandra and have run into various problems with Tombstones¹. These would cause detrimental issues when I would later run a query. For example, if I overwrite the same few rows over ...
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Joining in NoSQL to get chat messages for a user

In my chat app i have private / group chats and I need to get messages for a user. Let me first explain the whole system. Messages: // group message { id: 1, text: 'hello', chat_id: 'AjK954_e5iP'...
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Can Cassandra split a table?

I am sorry if this is basic question; I'm still ramping up on Cassandra. Problem: Let's say I had a table. Each entry has a unique user ID as a "row key" and three columns (City, State, and ...
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Query Performance improvement in Cassandra

I have a table in my Cassandra db. CREATE TABLE table ( pk uuid, status int, location text, type text, id text, updatedtimestamp timestamp, PRIMARY KEY (pk) ); CREATE ...
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Filtering a large number of rows in Cassandra

Let's assume we have a lot of potentially heavy rows (e.g. 500k) in a table that we want to filter by primary keys and send over the internet to a processing engine.Is it reasonable to use the IN ...
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Steps to restart a node in Cassandra cluster

We have Cassandra cluster of 3 nodes in the same rack. Now as part of regular maintenance activities on the server, I want to stop and start once instance of the Cassandra on one node at a time. We ...
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What does the node health value in a Datastax node compose of?

On a datastax Cluster (6.7.8) I can run: nodetool node_health --all This gives a list of values for the cluster with IP addresses and health values - eg IP Address Node Health 1.2.3.4 1.0 1.2....
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Tip on modeling Cassandra database schema time querry

I am working on modeling a database schema for Cassandra from existing relational schema, so in my database there are "events" (some events are scheduled events, some are recurring events) ...
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Cassandra Table data modeling for a event system monitoring data

I have been working in a cassandra database to keep the real time data of an event/monitoring system that has quite a large number of events per hour(100k+) and I have hit a wall in a specific need: I ...
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Multi level Sharding in Cassandra

I am sorry if this is basic question. I am new to Cassandra and need help on a query. Assume I want to host a service which accepts SurveyMonkey , now users are given a URL to take the survey and at ...
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Why Cassandra is not considered a relational database?

Read this answer Relational databases are based on the relational model, an intuitive, straightforward way of representing data in tables. In a relational database, each row in the table is a record ...
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Which NoSQL for storing images as 2D arrays (BLOBs)

I have large number of images that I need to access on per-pixel-basis in my app. The images are downloaded from web and are quite large (4k). Update is done several times a day (tousands of images), ...
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is there a DDL generator out there where you can start with CSV/TSV to create DDL for Cassandra

Is there a DDL generator out there where you can start with CSV/TSV (or maybe even JSON) to create DDL for Cassandra?
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Cassandra nodetool repair open files issue

I am using Cassandra 3.6. After nodetool repair Cassandra start takes too much time. The message is: ViewManager.java:226 - Not submitting build tasks for views in keyspace system_schema as storage ...
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Elassandra data modeling

In Cassandra, everyone always stresses how important data modeling is, and rightfully so. However, when using Elassandra, we have Elasticsearch baked in. How does should change how we think about ...
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Cassandra security - private IPs with some VPN solution or public IPs and open ports?

there are many different solutions to secure a cassandra cluster. One of them is to enter public IPs and open the 7000/9042 port on each sever. Another one is to have everything in a private network ...
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Read from partition in local cassandra node only

I'm aware that I can read from any cassandra node and it acts as coordinator to read from the node containing a specific partition, but can I read data only from the partition which is on the node I'm ...
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Cassandra goes down after some some days

I am running cassandra in 3 node cluster with replication factor 3. It was working fine for 2 days and all of a sudden it went down. I am beginner to cassandra database. I went through documentation ...
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does a php 7.3 cassandra driver exist?

I have php 7.3 on Debian 10. I'm trying to get the Apache Cassandra driver for php 7.3. The one provided by datastax (https://github.com/datastax/php-driver) only works up to 7.1, and the pecl one (...
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Cassandra query response time degradation

I am experimenting with Cassandra on 4 sites with 2 nodes on each one. Have small network latency between them. I always query the data in DC where I inserted it. I see very strange behavior: when I ...
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How to insert nested UDT types

I have all these case classes :- case class Role(id:UUID, roleName:String, description:Option[String], isVisible:Boolean, isDefault:...
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Cassandra not returning the row of the specified primary key

First of all, my table is structured like this: CREATE TABLE timeseries_data.test_data ( date timestamp PRIMARY KEY, data1 float, data2 float ) WITH bloom_filter_fp_chance = 0.01 AND ...
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What happens if one DC goes down in Cassandra multi DC setup?

We have a Cassandra multi DC setup with 3 nodes in each DC, enabled with NetworkTopologyStrategy and RF 3. The java client interacts with Cassandra cluster using read and write consistency as ...
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compaction strategies and high performance storage

My apologies for this being a somewhat newbie question. However, my understanding of Cassandra is that is use three different compaction strategies: are these tunable, or is this area a black box, i....
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Querying a High Cardinality Field

I am designing a data model for our orders for our upcoming Cassandra migration. An order has an orderId (arcane UUID field) and an orderNumber (user-friendly number). A getOrder query can be done by ...
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Cassandra data modelling for IOT devices

We are building a micro service based IOT platform with a dashboard and views of various sensors etc. I have seen a few data modelling videos but I am not able to arrive at a good data model in ...
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Cassandra slow read performance after migrating to new AWS instance class

Cluster of 3 cassandra nodes as a dev environment. Used to run in AWS on i3.2xlarge; migrated as a test to i3en.2xlarge to evaluate for later migrating production cluster to. When running cassandra-...
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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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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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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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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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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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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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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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2 votes
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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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2 votes
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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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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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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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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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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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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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3 votes
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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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