Mirror of Apache Cassandra

Last update: Jan 1, 2023

Overview

Apache Cassandra

Apache Cassandra is a highly-scalable partitioned row store. Rows are organized into tables with a required primary key.

Partitioning means that Cassandra can distribute your data across multiple machines in an application-transparent matter. Cassandra will automatically repartition as machines are added and removed from the cluster.

Row store means that like relational databases, Cassandra organizes data by rows and columns. The Cassandra Query Language (CQL) is a close relative of SQL.

For more information, see the Apache Cassandra web site.

Requirements

Java >= 1.8 (OpenJDK and Oracle JVMS have been tested)
Python 3.6+ (for cqlsh; 2.7 works but is deprecated)

Getting started

This short guide will walk you through getting a basic one node cluster up and running, and demonstrate some simple reads and writes. For a more-complete guide, please see the Apache Cassandra website’s Getting Started Guide.

First, we’ll unpack our archive:

$ tar -zxvf apache-cassandra-$VERSION.tar.gz
$ cd apache-cassandra-$VERSION

After that we start the server. Running the startup script with the -f argument will cause Cassandra to remain in the foreground and log to standard out; it can be stopped with ctrl-C.

$ bin/cassandra -f

Now let’s try to read and write some data using the Cassandra Query Language:

$ bin/cqlsh

The command line client is interactive so if everything worked you should be sitting in front of a prompt:

Connected to Test Cluster at localhost:9160.
[cqlsh 2.2.0 | Cassandra 1.2.0 | CQL spec 3.0.0 | Thrift protocol 19.35.0]
Use HELP for help.
cqlsh>

As the banner says, you can use 'help;' or '?' to see what CQL has to offer, and 'quit;' or 'exit;' when you’ve had enough fun. But lets try something slightly more interesting:

cqlsh> CREATE KEYSPACE schema1
       WITH replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
cqlsh> USE schema1;
cqlsh:Schema1> CREATE TABLE users (
                 user_id varchar PRIMARY KEY,
                 first varchar,
                 last varchar,
                 age int
               );
cqlsh:Schema1> INSERT INTO users (user_id, first, last, age)
               VALUES ('jsmith', 'John', 'Smith', 42);
cqlsh:Schema1> SELECT * FROM users;
 user_id | age | first | last
---------+-----+-------+-------
  jsmith |  42 |  john | smith
cqlsh:Schema1>

If your session looks similar to what’s above, congrats, your single node cluster is operational!

For more on what commands are supported by CQL, see the CQL reference. A reasonable way to think of it is as, "SQL minus joins and subqueries, plus collections."

Wondering where to go from here?

Join us in #cassandra on the ASF Slack and ask questions
Subscribe to the Users mailing list by sending a mail to [email protected]
Visit the community section of the Cassandra website for more information on getting involved.
Visit the development section of the Cassandra website for more information on how to contribute.

Comments

CASSANDRA-17837 Add pull request template and update readme
Pull request Description: Adds pull request template that looks like this form. This should be applied to all released and official development branches.

Issue resolved: CASSANDRA-17837

or

[ ] this is a trivial documentation change. (e.g. fixes a typo)

[ ] Commits have been squashed to remove intermediate development commit messages.

[ ] Key commit messages start with the issue number (CASSANDRA-xxxx)

if not a trivial change:

[ ] Jira ticket contains a description of: what is fixed, why it is needed, and what branches to apply it to.

[ ] Tests are included.

[ ] Documentation changes and/or updates are included.

[ ] By submitting this pull request, I acknowledge that I am making a contribution to the Apache Software Foundation under the terms and conditions of the Contributor's Agreement.

References:

The Apache Cassandra "Contributing to Cassandra" guide

The Apache Cassandra "Working on Documentation" guide

The Apache Contributor's Agreement.
opened by Claudenw 45
CASSANDRA-17750: Remove Maven Ant Tasks

Jira: https://issues.apache.org/jira/browse/CASSANDRA-17750 CircleCI: https://app.circleci.com/pipelines/github/aratno/cassandra?branch=CASSANDRA-17750-remote-maven-ant-tasks

opened by aratno 45

CASSANDRA-17753: Include GitSHA in nodetool version output

Jira: https://issues.apache.org/jira/browse/CASSANDRA-17753 CircleCI: https://app.circleci.com/pipelines/github/aratno/cassandra?branch=CASSANDRA-17753-nodetool-version-gitsha

# When Cassandra is built with a clean Git index
$ ./bin/nodetool version
ReleaseVersion: 4.1-alpha2-SNAPSHOT
GitSHA: 5fce07e2f1e2e0b9cf7d82adfd8c0b21993f8672

# When Cassandra is built with a dirty Git index
$ ./bin/nodetool version
ReleaseVersion: 4.1-alpha2-SNAPSHOT
GitSHA: 5fce07e2f1e2e0b9cf7d82adfd8c0b21993f8672-dirty

opened by aratno 10

Enable dtest-offheap in CircleCI

The dtest-offheap test was only added to the Jenkins configuration, so this commit adds it to the CircleCI build for parity. Because dtest-offheap in Jenkins is configured to skip resource intensive tests, the dtest-offheap suite is added to all three sets (LOW, MEDIUM, HIGH).

Patch by Derek Chen-Becker; reviewed by Ekaterina Dimitrova for CASSANDRA-17950

opened by dchenbecker 8
CASSANDRA-14790 Fix flaky LongBufferPoolTest
The LongBufferPoolTest previously required significantly more heap memory on machines with higher core count.

This PR

adds commands to the build system to allow running individual burn tests (in and outside junit)

fixes some race conditions that occur when the test is running under heavy memory pressure

changes the calculation for how much memory the ring-of-threads should allocate to be roughly double the pool size under test. It now completes with much less memory and should run fine on a builder.
opened by jonmeredith 8
CASSANDRA-17444 Update document properties heading.

Update document properties heading. The headline was different from the rest of the page in the formato, so it has been corrected.

This page. https://cassandra.apache.org/doc/latest/cassandra/configuration/cass_topo_file.html https://cassandra.apache.org/doc/latest/cassandra/configuration/cass_cl_archive_file.html

Other page. https://cassandra.apache.org/doc/latest/cassandra/configuration/cass_yaml_file.html
docs

opened by taku333 6
Cassandra 18134

patch by ; reviewed by for CASSANDRA-18134

Co-authored-by: Branimir Lambov Co-authored-by: Sylvain Lebresne Co-authored-by: Jacek Lewandowski Co-authored-by: Jakub Zytka

The Cassandra Jira

opened by jacek-lewandowski 0
"the"">
Fix typo "the-the" -> "the"
I searched the entire repository for the *.md files and didn't spot any more of such typos. Here is the command:

find . -not -path "./.git/*" -type f -name "*.md" -exec grep --color "\(\b\w\+\)\b\s*\1\b" {} \+
docs
opened by neshkeev 0
[CASSANDRA-16418]: Unsafe to run nodetool cleanup during bootstrap or decommission
Changes:

Added check during cleanup to ensure the node has no pending ranges before proceeding

Bug from JIRA ticket did not exist for bootstrap due to existing safety check but the check was one level below other safeguard checks so moved it to same location

To reproduce, run cleanup on a node receiving data while another node is being decommissioned. I created 20 sstables of data.

patch by Lindsey Zurovchak; reviewed by Paulo Motta for CASSANDRA-16418
opened by linzuro 0
[CASSANDRA-11537] Friendly error message when nodetool is used on uninitialized Cassandra node

CASSANDRA-11537

To reproduce this, you can run a loop on a nodetool command while a Cassandra node is initializing. I used ring.

patch by William Nguyen; reviewed by Paulo Motta for CASSANDRA-11537

opened by williamvietnguyen 0