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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questions with no upvoted or accepted answers
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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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Data modelling for dynamic grouping of rows in Cassandra
I have a feed of game events with a schema like;
{
"gameId": text,
"playerId": text,
"eventId": text,
"ts": bigint,
"metrics": map<...
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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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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 ...
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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 ...
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1
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33
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How do I backup data of Cassandra nodes running in Docker?
I hope to receive some tips and assistance.
I have three virtual machines running Ubuntu 22.04, and each one has Cassandra deployed via docker-compose, forming a cluster.
My current task is to ...
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2
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1
answer
82
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Single node failure in Cassandra 4.0.7 causes cluster to run into high CPU
we have 40 node Cassandra 4.0.7 cluster in GCP, after single node failure the entire cluster goes bonkers on CPU usage and I/O waits. Tried to bump the cluster size to 50 nodes the same is happening ...
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2
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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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Repair running too slow
Last week I asked a question that was answered below... I need to improve the question I asked earlier (in quotes below) and give a little more context. The answer below did help the repair ...
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Cassandra's nodetool snapshot renders node unresponsive
I have noticed that using nodetool snapshot on a Cassandra node causes heavy load (100% on two cores) for around 10-30 seconds. The snapshots are around 1GB in size. During that time connections to ...
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What are the implications of using quite large partitions (rows) in Cassandra?
I am looking to store data in Cassandra, due to the fact that I have many writes that need to perform well, and all my reads can be done based on primary key. While doing the data modeling, however, I ...
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151
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Update a Record in Cassandra
I'm having the following query while updating a particular record.
I've a user Column Family CF as follow:-
class User(Model):
user_id = UUID(default=uuid.uuid4,primary_key= True)
date = ...
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Cassandra Deployement Architecture
I'm new to Cassandra. I have the responsibility to design a basic deployment architecture for a use case. I'd like to know if my solution is correct, and get advice and recommendations from you.
Here ...
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Strugling with updating a cassandra row in FluentCassandra
I have this problem with using Fluent Cassandra in a test application. All I want to do is set the IsOnline field to true inside the SignIn method, but I keep getting the exception supercolumn ...
2
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1
answer
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Is there a configuration option that lets me limit the percent of a hard drive that Cassandra uses?
I'm doing some testing with a small hard disk and I'd like to basically stop Cassandra in its tracks if a write or compaction or any other service brings that usage of the disk above a certain ...
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How to reduce Backpressure rejection while receiving WRITES and increase throughput limit of cluster
After we rebuild a down node we could see some other nodes are going down and its prompting "Backpressure rejection while receiving WRITES". Nodes are behaving as down and its continuing for ...
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nodetool rebuild returned "Unable to find sufficient sources for streaming range"
We are migrating self hosted cassandra 3.11.6 to self hosted cassandra with k8ssandra-operator using cassandra 3.11.7.
At some point of the migration we had to stop it due to other unrelated incident. ...
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1
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What is the difference between nodetool commands "garbagecollect" vs "compact"?
What is the difference between working procedure of below 2 commands. How differently these are working
nodetool garbagecollect
and
nodetool compact -s
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1
vote
1
answer
48
views
SELECT COUNT() returns ReadFailure after importing data from another cluster
I've cloned one cluster to another with these steps:
Copy table files on each source node from /var/lib/cassandra/data/keyspace/table/snapshots... to /location/snaps/
Run sstableloader on each ...
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1
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70
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Is Cassandra 4.1 not compatible with Ubuntu 20.04?
I can't make connection into my nodecluster, my nodetool status is currenty refused, i am using Cassandra 4.1 but not working trying edit in cassandra.yaml for localhost using 127.0.0.1 also edit my ...
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How do I model a Cassandra table that stores friends of a user?
Recently I started to learn Cassandra. I needed to design the database for my web application. So, I prepared conceptual data model as well as application workflow, and currently I’m stuck on ...
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Cassandra can't start with an old backup of /var/lib/cassandra
I have an old Cassandra backup of /var/lib/cassandra on an external drive and I want to setup a new database with this backup.
I install the same Cassandra version as then and in the yaml file I ...
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Cassandra System.Log shows nodtool tpstats output
We have a Docker Cassandra container running 6.8.21. At times when the container is restarted the the Logs show the usual startup activities and all just works well post that.
But on a few occasions ...
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vote
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207
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Disk space is not released after compaction
We have deleted some of the partionons of some tables in cassandra database. But after the delete space was not recliamed becuase of size-tiered compaction . Manualy compacted tables with -s options. ...
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34
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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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vote
1
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109
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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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230
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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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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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285
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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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223
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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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vote
0
answers
20
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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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152
views
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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486
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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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287
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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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649
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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answers
115
views
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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715
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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487
views
Increase timeout for cassandra native transport threads?
From the Cassandra documentation here
native_transport_max_threads
The maximum number of thread handling requests. Similar to rpc_max_threads, but this property differs as follows:
The ...
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Is my schema for a Discussion forum using Cassandra optimum or has a scope for improvement?
I am designing a Discussion Forum for my app which has following primary objects:
Image
Video
Text
Audio
The owner can start a discussion in context of any of the above object. Based on user ...
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0
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views
Is it possible to have a partition to distribute transaction load horizontally in SQL Server 2016?
In Cassandra, you can have a partition key to align partitions to particular server nodes.
My understanding is that you can distribute transactional responsibility horizontally in SQL Server 2016 (...
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views
What type of primary key we need to use for specific length of bits in Cassandra?
I want to know in which situations which type of primary key I need to use.
Situations:
1. If I need 64 bit key than is bigint is the best for it? If I will chose text type will performance will be ...
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Why restore a single node of a cluster?
We were reviewing the restore documentation for Cassandra here, and noted it made the following distinction between restoring a single node or an entire cluster:
If restoring a single node, you ...
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Setting up a 3-node cluster, getting exception "Unable to gossip with any peers"
Getting Gossip error when trying to setup 3 node cluster.
Node-1:
Private IP: 10.10.0.1
Public IP: public_ip_1
Node-2:
Private IP: 10.10.0.2
Public IP: public_ip_2
Node-3:
Private IP: 10.10.0.3
...
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9
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TTL in Cassandra
Can someone explain me how TTL actually works
For TWCS I see this process like this:
Within time window 1 we have data with some ttl (in SSTable1)
Then within the time window N the ttl of data from ...
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0
answers
6
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Unable to insert large number of records in Cassandra, please some solution
We are inserting large records of data into open Cassandra database one by one.. using asp.net core and it result into timeout and process hanged, so I want to know about bulk data insert process if ...
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1
answer
12
views
Newly added nodes showing as DN to each other in nodetool status output
I have recently installed Cassandra 4.1.1 in 5 node onPremise Cluster for my production environment..
For testing purpose I just added two seed nodes in Config file and restarted the Server and ...
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1
answer
12
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High IO usage, degraded performance after upgrading from Cassandra 3.11 to 4.1
After upgrading a 6 nodes Cassandra cluster from 3.11 to 4.1 the read performance degraded and IO usage is higher. Also during repairs the IO usage becomes very high ceiling on the aws node limit of ...
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2
answers
34
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How do I know if a repair is hung?
I have cluster cassandra-2.2.19-1 with 4 nodes. On one of the nodes, I ran nodetool repair --full, which has been going on for 3 days.
Datacenter: datacenter1
=======================
Status=Up/Down
|/ ...
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0
answers
14
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Not able to find casandra tables in apache spark
I started the spark by dse spark command.
Later I created a one rdd with cassandra keyspace and table ..
Trying to print contents of tables using rddname.first
But it shows couldn’t able to find ...
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1
answer
26
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Unable to start nodes after upgrading from Cassandra 3.11.13 to 4.0.5
I have 3 nodes cluster with version 3.11.13 built on Ubuntu 22.04 on EC2 and tried to upgrade to 4.0.5. I used apt install with openjdk-8-jdk for 3.11.13 and built the cluster with simplesnitch since ...
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