AWS
docs.aws.amazon.com › amazon redshift › database developer guide › sql reference › sql functions reference › leader node–only functions
Leader node–only functions - Amazon Redshift
A query that references only catalog tables (tables with a PG prefix, such as PG_TABLE_DEF) or that does not reference any tables, runs exclusively on the leader node. Some Amazon Redshift SQL functions are supported only on the leader node and are not supported on the compute nodes.
AWS
docs.aws.amazon.com › amazon redshift › database developer guide › sql reference › amazon redshift sql › sql functions supported on the leader node
SQL functions supported on the leader node - Amazon Redshift
In the next example, the query references an Amazon Redshift system table that resides on the compute nodes, so it returns an error. select current_schema(), userid from users; INFO: Function "current_schema()" not supported. ERROR: Specified types or functions (one per INFO message) not supported on Amazon Redshift tables. ... SUBSTR is also a leader-node only function.
Medium
medium.com › @KuldeepsinhVaghela › amazon-redshift-architecture-explained-leader-node-compute-nodes-and-performance-tuning-197ec98c6e7a
Amazon Redshift Architecture Explained: Leader Node, Compute Nodes, and Performance Tuning | by Kuldeepsinh Vaghela | Medium
April 24, 2025 - It runs the Redshift engine software responsible for query planning and workload management. While it has its own compute and memory resources, it does not store any user table data persistently. Its primary function is control and coordination.
ResearchGate
researchgate.net › figure › Amazon-Redshift-system-architecture-The-leader-node-accepts-connections-from-client_fig3_300581416
Amazon Redshift system architecture The leader node accepts connections... | Download Scientific Diagram
Download scientific diagram | Amazon Redshift system architecture The leader node accepts connections from client programs, parses requests, generates & compiles query plans for execution on the compute nodes, performs final aggregation of results when required, and coordinates serialization and state of transactions.
Panoply
panoply.io › data-warehouse-guide › redshift-architecture-and-capabilities
Buyer's Guide to Redshift Architecture, Pricing, and Performance | Panoply
Most projects require only one Redshift cluster; additional clusters can be added for resilience purposes (see this post by AWS on the subject). Each cluster comprises a leader node, which coordinates analytical queries, and compute nodes, which ...
Dwgeek
dwgeek.com › home › amazon redshift architecture and its components
Amazon Redshift Architecture and its Components - DWgeek.com
February 6, 2023 - The leader node in Redshift database is responsible for coordinating and executing SQL queries on behalf of the client application. When a client application submits a query to Amazon Redshift, the leader node parses it, and generates a optimal ...
GitHub
github.com › awsdocs › amazon-redshift-developer-guide › blob › master › doc_source › c_SQL_functions_leader_node_only.md
amazon-redshift-developer-guide/doc_source/c_SQL_functions_leader_node_only.md at master · awsdocs/amazon-redshift-developer-guide
A query that references only catalog tables (tables with a PG prefix, such as PG_TABLE_DEF) or that does not reference any tables, runs exclusively on the leader node. Some Amazon Redshift SQL functions are supported only on the leader node and are not supported on the compute nodes.
Author awsdocs
Wordpress
piyushchaudhariblog.wordpress.com › 2018 › 09 › 27 › amazon-redshift-architecture-and-its-components
Amazon Redshift Architecture and Its Components | My Passion Behind Blogging
September 27, 2018 - The Leader Node is responsible for assigning a Query code and data to a slice for execution. Slices once assigned query load work in parallel to generate query results. Data is distributed among the Slices on the basis of Distribution Style ...
Softcrylic
softcrylic.com › home › performance tuning in aws redshift
Performance Tuning in AWS Redshift - Softcrylic
December 21, 2021 - The leader node’s job is to assign a query to the slices for execution. Once the query is assigned, it works in parallel to generate the query results. Data is distributed to slice based on distribution style and distribution key of table.
Analytics Vidhya
analyticsvidhya.com › home › what is amazon redshift & spectrum in aws?
What is Amazon Redshift & Spectrum in AWS? - Analytics Vidhya
June 29, 2023 - When any query is submitted to the leader node, it is passed to each slice for execution on the data present in that slice. There are benefits to distributing data across many slices. Once a cluster is created, the node count may be altered by cluster resize. Redshift supports two resize approaches, classic and elastic.
AWS
docs.aws.amazon.com › amazon redshift › database developer guide › introduction to amazon redshift › amazon redshift architecture › data warehouse system architecture
Data warehouse system architecture - Amazon Redshift
The leader node manages distributing data to the slices and apportions the workload for any queries or other database operations to the slices. The slices then work in parallel to complete the operation. The number of slices per node is determined by the node size of the cluster.
AWS
docs.aws.amazon.com › amazon redshift › management guide › amazon redshift provisioned clusters
Amazon Redshift provisioned clusters - AWS Documentation
The leader node receives queries from client applications, parses the queries, and develops query execution plans. The leader node then coordinates the parallel execution of these plans with the compute nodes and aggregates the intermediate results from these nodes.
ProsperOps
prosperops.com › home › exploring amazon redshift architecture: a comprehensive guide
Exploring Amazon Redshift Architecture: A Comprehensive Guide - ProsperOps
September 19, 2024 - Leader nodes are in charge of query execution and data distribution within the Redshift clusters. Whenever a data query comes in from the client applications or a user queries a database, the leader nodes parse the query and create an execution plan.
Top answer 1 of 3
1
In an Amazon Redshift cluster, the leader node type is not explicitly specified or chosen separately from the compute nodes. When you set up a Redshift cluster, you specify the node type (such as RA3 or DC2) and this applies to the compute nodes. The leader node is automatically provisioned as part of the cluster, but its specifications are not directly tied to the compute node type you select.
The leader node manages communications with client applications, parses queries, develops query execution plans, and coordinates the parallel execution of these plans with the compute nodes. It also aggregates intermediate results from compute nodes before returning final results to client applications.
Unlike compute nodes, where you can specify the number and type (like your example of 3 RA3.xlplus nodes), the leader node is provided automatically as part of the cluster architecture. The documentation doesn't specify that the leader node is of the same type as your compute nodes.
The leader node's resources are managed by Amazon Redshift to handle its coordination responsibilities, regardless of the compute node type you choose for your cluster.
**Sources**
Amazon Redshift provisioned clusters - Amazon Redshift
Data warehouse system architecture - Amazon Redshift
Architecture components of an Amazon Redshift data warehouse - AWS Prescriptive Guidance
2 of 3
0
Based on the AWS documentation, in an Amazon Redshift cluster, the Leader node is handled differently than the compute nodes.
When you set up a Redshift cluster with 3 ra3.xlplus compute nodes, here's what happens with the Leader node:
**Leader Node Configuration:**
* The Leader node is automatically provisioned and managed by Amazon Redshift
* You do not directly choose or specify the Leader node type
* Its specifications are determined by Amazon Redshift based on your overall cluster configuration
**Leader vs. Compute Nodes:**
* While your compute nodes are all ra3.xlplus in your example, the Leader node is not necessarily the same type
* The Leader node's resources are automatically scaled by AWS to match the needs of your cluster
* The exact specifications of the Leader node are not directly visible or configurable by users
So to directly answer your question: In a cluster with 3 ra3.xlplus compute nodes, the Leader node is not necessarily an ra3.xlplus node. Its type and specifications are managed internally by AWS and are not explicitly exposed to users. The Leader node is provisioned with appropriate resources to efficiently manage your specified compute nodes.
This approach allows Amazon Redshift to optimize the Leader node's capabilities based on the specific requirements of your cluster configuration without requiring you to make these technical decisions.
Integrate.io
integrate.io › home › blog › big data integration › aws redshift architecture: clusters & nodes & data apps
AWS Redshift Architecture: Clusters & Nodes & Data Apps | Integrate.io
July 21, 2025 - Distribution of workloads: The leader node parses queries, develops an execution plan, compiles SQL into C++ code, and then distributes the compiled code to the compute nodes. Caching of query results: When a query is executed in Amazon Redshift, ...
Stack Overflow
stackoverflow.com › questions › 46234800 › aws-redshift-leader-node-only-function-with-table-reference
sql - AWS Redshift Leader Node-Only Function with table reference - Stack Overflow
September 15, 2017 - ERROR: 0A000: Specified types or functions (one per INFO message) not supported on Redshift tables. I understand that this query does not work because I am trying to execute a Leader Node-Only Function in conjunction with a query which needs to access the compute nodes.
Saturn Cloud
saturncloud.io › blog › understanding-aws-redshift-leader-nodeonly-functions-and-table-references
Understanding AWS Redshift Leader Node-Only Functions and Table References | Saturn Cloud Blog
September 9, 2023 - In this blog post, we will dive into AWS Redshift's leader node-only functions and how they can be used with table references. As data scientists, we often need to work with large datasets and perform complex data processing tasks. AWS Redshift is a powerful, fully managed data warehouse service ...
Orchestra
getorchestra.io › guides › describe-reserved-node-offerings-with-aws-redshift-python-sdk
Describe Reserved Node Offerings with AWS Redshift Python SDK | Orchestra
July 3, 2024 - Query Parsing and Planning: The leader node receives queries from client applications. It parses the SQL queries, develops an optimized execution plan, and coordinates the distribution of the work to the compute nodes.