How would you describe keyspace in Cassandra?

A keyspace is an object that is used to hold column families, user defined types. A keyspace is like RDBMS database which contains column families, indexes, user defined types, data center awareness, strategy used in keyspace, replication factor, etc. In Cassandra, “Create Keyspace” command is used to create keyspace.

What is simple strategy in Cassandra?

SimpleStrategy in Cassandra SimpleStrategy is used when you have just one data center. SimpleStrategy places the first replica on the node selected by the partitioner. After that, remaining replicas are placed in clockwise direction in the Node ring.

What are replication strategies supported in Cassandra?

Two replication strategies are available:

• SimpleStrategy : Use only for a single datacenter and one rack.
• NetworkTopologyStrategy : Highly recommended for most deployments because it is much easier to expand to multiple datacenters when required by future expansion.

What are all the different types of replication strategies in Cassandra?

These are explained as following below.

• SimpleStrategy: It is a simple strategy that is recommended for multiple nodes over multiple racks in a single data center.
• Creating a keyspace:
• LocalStrategy:
• NetworkTopologyStrategy:
• System and system_auth Keyspaces:

What is the default keyspace in Cassandra?

A default keyspace can be defined for each session created off the main connection object. Without this option, each table will need its corresponding keyspace specified with each query. This option is useful for clusters which have only one (non-system) keyspace.

Is Cassandra strong consistency?

Cassandra prefers availability over consistency. It doesn’t optimize for consistency. Instead, it gives you the flexibility to tune the consistency depending on your use case. In most use cases, Cassandra relies on eventual consistency. Let’s look at consistency level impact during the write and read of data.

How do I change the replication strategy in Cassandra?

Procedure

1. Change the snitch to a network-aware setting.
2. Alter the keyspace properties using the ALTER KEYSPACE command.
3. Alter the keyspace properties using the ALTER KEYSPACE command.
4. Run nodetool-repair using the -full option on each node affected by the change.

How do I see all tables in a keyspace in Cassandra?

1. Get keyspaces info. SELECT * FROM system_schema.keyspaces;
2. Get tables info. SELECT * FROM system_schema.tables WHERE keyspace_name = ‘keyspace name’;
3. Get table info. SELECT * FROM system_schema.columns WHERE keyspace_name = ‘keyspace_name’ AND table_name = ‘table_name’;

Which replication strategy is used in Cassandra for multiple data center?

1. SimpleStrategy: It is a simple strategy that is recommended for multiple nodes over multiple racks in a single data center.

What is quorum in Cassandra?

Quorum consistency is consistency in Cassandra for high mechanism and to ensure that how many nodes will respond when we will define the read and write consistency in Cassandra. In Quorum consistency a majority of (n/2 +1) nodes of the replicas must respond.

Is Cassandra good for read or write?

Cassandra is excellent for write operations but not so fast on read operations. Both are rather fast but Cassandra does write operation faster. Cassandra has benefits being +HA (no SPOF) + having tuneable Consistency. Cassandra is very fast writing bulk data in sequence and reading them sequentially.

How does quorum work in Cassandra?

How do I change the keyspace replication factor in Cassandra?

If you want to change the replication factor of a keyspace, you can do it by executing the ALTER KEYSPACE command, which has the following syntax: Syntax: ALTER KEYSPACE “KeySpace Name” WITH replication = {‘class’: ‘Strategy name’, ‘replication_factor’ : ‘No. Of replicas’};

What is the role of replication factor in keyspace?

The replication strategy for each Edge keyspace determines the nodes where replicas are placed. The total number of replicas for a keyspace across a Cassandra cluster is referred to as the keyspace’s replication factor. A replication factor of one means that there is only one copy of each row in the Cassandra cluster.

What is quorum consistency?

What is Quorum Consistency? Quorum consistency is consistency in Cassandra for high mechanism and to ensure that how many nodes will respond when we will define the read and write consistency in Cassandra. In Quorum consistency a majority of (n/2 +1) nodes of the replicas must respond.

What is a keyspace in Cassandra?

A keyspace in Cassandra is a namespace that defines data replication on nodes. A cluster contains one keyspace per node. Given below is the syntax for creating a keyspace using the statement CREATE KEYSPACE. The CREATE KEYSPACE statement has two properties: replication and durable_writes.

What are the different types of strategies in Cassandra?

Strategy: There are two types of strategy declaration in Cassandra syntax: Simple Strategy: Simple strategy is used in the case of one data center. In this strategy, the first replica is placed on the selected node and the remaining nodes are placed in clockwise direction in the ring without considering rack or node location.

Is it possible to set the create keyspace property to simplex strategy?

There is another property of CREATE KEYSPACE in Cassandra. By default, the durable_writes properties of a table is set to true, you can also set this property to false. But, this property cannot be set to simplex strategy.

How do I change the strategy of a keyspace?

A keyspace is created with a strategy. For development work, the SimpleStrategy class is acceptable. For production work, the NetworkTopologyStrategy class must be set. To change the strategy, two steps are required. Change the snitch to a network-aware setting.