Amazon Redshift introduces a unique identifier assigned to SQL queries, which lets you effectively track query performance over time and identify recurring patterns in resource-intensive queries. This new feature, called a ‘query hash’, uniquely identifies SQL queries based on their textual representation and predicate values.
Query hash is a unique query signature that is generated for executed queries on a data warehouse. With query hash, you can investigate query performance by either performing trend analysis of queries over a period of time or comparing performance for a query across different time periods. This feature adds two new columns to SYS_QUERY_HISTORY view: user_query_hash, a hash with query literals, and generic_query_hash, the hash without query literals.
Amazon Redshift query hash is now generally available for both Amazon Redshift provisioned clusters and Amazon Redshift Serverless data warehouses in all AWS commercial and the AWS GovCloud (US) Regions where Amazon Redshift is available. To get started and learn more, visit the Amazon Redshift database developer guide.
Source:: Amazon AWS