Cluster Components
Warning
SingleStore 9.0 gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 8.9 is recommended for production workloads, which can later be upgraded to SingleStore 9.0.
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Key Components
The following components are fundamental to a SingleStore cluster.
Cluster
A cluster encompasses all of the nodes that are included in a complete SingleStore DB installation.
A cluster contains aggregator nodes and leaf nodes.
Node
A node is a server that has an installation of a SingleStore DB instance.
See Node Requirements for SingleStore Commands to learn about the commands supported by different types of nodes.
Leaf
A leaf is a node that stores a subset of a cluster’s data.
Partition
A partition contains a subset (a shard) of a database’s data.CREATE DATABASE
, you can specify the number of partitions with the PARTITIONS=X
option.
If you don’t specify the number of partitions explicitly, the default is used (the number of leaf nodes times the value of the default_
engine variable.
Tables
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Universal Storage - (Default) Supports large-scale Online Transaction Processing (OLTP) and Hybrid Transactional and Analytical Processing (HTAP) workloads at a lower total cost of ownership (TCO).
Universal Storage is a continuing evolution of the columnstore and supports transactional workloads that would have traditionally used the rowstore. SingleStore recommends using the Universal Storage tables for all kinds of workloads. -
Rowstore - In-memory rowstore tables for high-performance OLTP workloads.
SingleStore stores data in tables, which can be of one of the following types:
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Sharded or Reference - A sharded table’s data is distributed across partitions.
By contrast, a reference table’s data is replicated, in full, to all nodes in a cluster. -
Persisted or Temporary - Defines whether the data stored in a table is persisted or stored temporarily for the duration of a client session.
Temporary tables can further be classified into regular temporary tables and global temporary tables.
The tables can have the following properties:
Aggregator
An aggregator is a node that routes queries to the leaves, aggregates the intermediate results, and sends the results back to the client.
A master aggregator
is a specialized aggregator responsible for cluster monitoring and failover.
A cluster contains exactly one master aggregator.
Aggregator to Leaf Ratio
The minimal setup for a SingleStore cluster is just one aggregator (the master aggregator) and one leaf.
The number of deployed aggregator and leaf nodes determines the storage size and performance of a cluster.
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Applications that require higher connection capabilities from application servers have a higher aggregator-to-leaf node ratio.
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Applications with larger storage requirements have a higher leaf-to-aggregator node ratio.
Last modified: June 22, 2022