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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Small startup: Cassandra + Hadoop or ElasticSearch

To give some context, I am from a small start up (4 team members) and we work in the education space. We've developed an e-learning platform that several schools are already using. We currently have ...
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How to create multiple graphs with TitanDB (+Cassandra) in the same machine?

I'm experimenting with TitanDB (with Cassandra as storage) + Rexter. I've been reading the documentation during hours and trying to create multiple graph DBs on the same machine, but I didn't find ...
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246 views

Which database to use? [closed]

Hey there. I am looking for a free to use for commercial website database that should have these design features, in the given order: Auto-Sharding (getting more free space by adding more server ...
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60 views

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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1answer
96 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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292 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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1answer
130 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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96 views

Cassandra 3.11 commit logs nightmare

Clean installs of Cassandra 3.11 nodes are working fine for me for a few days, and then ‘nodetool flush’ and ‘nodetool compact’ are starting to throw exceptions. After this, restarts after a ‘nodetool ...
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403 views

What may be the consequences of deleting the system keyspace?

I have a Cassandra cluster composed of 2 nodes. One node could not start Cassandra yesterday. I deleted the system keyspace directory and I started the node again. The node is running after system ...
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1answer
146 views

DSE Cassandra decimal type

I generated solrschema with dsetool on a table name seriesdata (its key is composed by seriesmetadata_id, initialtime; two decimal field). These fields are defined as DecimalStrField but they are ...
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2answers
279 views

Cassandra query performs differently at different times

I am using apache-cassandra-2.0.12 in production, with network topology strategy and ReplicationFactor : 3 in a cluster with 2 DC’s each contains 4 nodes While analyzing the response time for the ...
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238 views

Cassandra in a Public Cloud - Which Snitch?

I am planning on deploying Cassandra in a public cloud (like Amazon AWS). The cluster will span multiple zones and regions. The cluster will also require logical DC separation within a given region. ...
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278 views

Cassandra upgrade/repair issues in migration

I wanted to migrate part of the column families in a cluster to a new cluster. I made a snapshot of the source cluster and copied the data, made a new cluster with the same name, same number of nodes ...
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4k views

What is different bettween Cassandra NoSQL data model and SQL data model

can any one tell. cassandra data model and sql data model how we can define row and column with cassandra data model?
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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 - 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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356 views

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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96 views

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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1answer
124 views

Binary storage in Cassandra, HBase

I am looking at some implementations of Cassandra and HBase for medium-sized data sets (~1M resources) to be exposed to clients as graphs (via e.g. Tinkerpop). I would also like to store binaries in ...
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277 views

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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130 views

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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85 views

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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321 views

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 ...
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1answer
39 views

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 does Apache Cassandra handle dynamic column set conflicts?

I know that each column in Apache Cassandra has a timestamp attached and that read conflicts for a single column is resolved deterministically by looking at timestamp or by comparing the value. Let's ...
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759 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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528 views

Correct way to perform backup of Cassandra/Scylladb

What's the correct(advisable) method to backup a cassandra or scylladb so that we can restore it on development environment with ease?
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258 views

What's the advantage of the inet datatype in Cassandra vs a plain text string?

What is the inet datatype really for? The documentation refers to its usage having something to do with Python but I'm not much of a Python guy so that aspect is beyond me. Is there any advantage to ...
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309 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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1answer
633 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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184 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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351 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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240 views

Repair going very slow

We have a 32 node cluster with an average of approximately 150GB of data on each node. When running a full repair (not doing primary range) it is taking approximately 26 hours to complete. This seems ...
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199 views

Are most of the NoSQL databases key/value stores technically? [closed]

This video distinguishes between three (main) types of NoSQL databases: Key/Value store Tabular Document oriented Do these types differ in how they technically store their data or can they be ...
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66 views

Error after upgrading datastax to version 5

After upgrading to DataStax Enterprise version 5, the node does not come up, and I get this error in the log: Insufficient permissions on directory /hints Where is this directory located?
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780 views

cassandra in memory tables

I am planning to use Cassandra in memory tables for my particular work load. THe problem is I am worried if the node fails then what will happen to the data in memory that was not flushed to disk ? ...
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1answer
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Allow filtering not working as expected

I'm having issues with getting ALLOW FILTERING to work. In our Cassandra 1.2 database, we have a table like this: CREATE TABLE some_table partition_key text, other_key text, non_key ...
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2answers
4k views

Cassandra in multiple data center - EC2MultiRegionSnitch

I was reading article from : http://www.datastax.com/docs/1.0/cluster_architecture/replication#networktopologystrategy and I have a question about - EC2MultiRegionSnitch. I did not understand it well. ...
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680 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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67 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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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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51 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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184 views

sstableloader returns `java.lang.NumberFormatException: For input string: “Filter.db”`

I've been using the Java API to create an SSTable by following the instructions on this site. The program compiles and works fine; no errors. However when I try to load the table using the following ...
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113 views

Cassandra change replication factor hive datastore

I am trying to change replication factor of HiveMetaStore but I receive this message: cassandra@cqlsh:system> alter KEYSPACE HiveMetaStore with replication = {'class': '...
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1answer
155 views

How to predict new node allocation in a Cassandra cluster?

I have a 5-node Cassandra cluster. Each node has disk space of 5TB. The real usage for each node is around 2.5TB depending on allocations and compactions (some are around 2TB some around 2.8). I ...
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205 views

How to Query Properties of an Entity in Apache Cassandra

I am new to Apache Cassandra, and I would like to know how to create a table in which I can filter rows by non-key columns. In relational databases, I would simply create a table with an ID as a ...
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1answer
919 views

Cassandra: memtable_offheap_space_in_mb and memtable_cleanup_threshold

I use C* v2.1.2 do write only workload (into one column family) and experiment with offheap-objects memtable space. I set parameters to: memtable_offheap_space_in_mb = 51200 # 50Gb ...
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1answer
572 views

Date model for commenting system stored in a key-value NoSQL DB?

I'm trying to leverage Cassandra's strong support for time series data to build a commenting system. So far I'm thinking that each row would be a particular topic, and each comment would be a new ...
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3k views

Cassandra: Request did not complete within rpc_timeout

i was working with Cassandra 1.2.4 probably, after restoring some key-space when i tried to query in a key-space it gave me Request did not complete within rpc_timeout so i checked system.log & ...
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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 ...