The stored procedure can be called with confidence from a simple scheduler like cron. Stored procedures allow the ETL/ELT logical steps to be fully enclosed in a master procedure that is written so that it either succeeds completely or fails cleanly with no side effects. It can also be challenging to take on the operation and maintenance of an orchestration tool with a small data warehouse team. It can be difficult to ensure that shell scripts correctly retrieve and interpret the state of each operation in an ETL/ELT process. They can then allow other, less experienced operators to execute the process without entrusting them with full superuser permissions on the cluster.įinally, some customers prefer using stored procedures to manage their ETL/ELT operations as an alternative to shell scripting or complex orchestration tools. An experienced DBA is able to define a well-tested process for some administrative or maintenance action. With the security definer concepts in stored procedures, it is now possible to allow users to perform actions they otherwise would not have permissions to run.Īdditionally, using stored procedures in this way helps reduce the operations burden. Stored procedures offer new options to allow DBAs to perform necessary actions without having to give permissions too widely. Other customers would like to tighten security and limit the permissions of their database users. Using Amazon Redshift stored procedures allows you to migrate to Amazon Redshift more quickly. Re-creating the logic of these processes using an external programming language or a new ETL platform could be a large project. Many customers migrating to Amazon Redshift have complex data warehouse processing pipelines built with stored procedures on their legacy data warehouse platform. Complex transformations and important aggregations are defined with stored procedures and reused in many parts of their processing. For example, you can create stored procedures to perform functions without giving a user access to the underlying tables. You can also use stored procedures for delegated access control. By combining multiple SQL steps into a stored procedure, you can reduce round trips between your applications and the database. Stored procedures are commonly used to encapsulate logic for data transformation, data validation, and business-specific operations. You can use the PL/pgSQL procedural language, including looping and conditional expressions, to control logical flow. A stored procedure doesn’t have to return a value. Unlike a user-defined function (UDF), a stored procedure can incorporate data definition language (DDL) and data manipulation language (DML) in addition to SELECT queries. The procedure is stored in the database and is available to users who have sufficient privileges to run it. What is a stored procedure?Ī stored procedure is a user-created object to perform a set of SQL queries and logical operations. We also explain how to use stored procedures with AWS Schema Conversion Tool. In this post, we discuss how and where to use stored procedures to improve operational efficiency and security. With that primary goal in mind, AWS chose to implement PL/pqSQL stored procedure to maximize compatibility with existing procedures and simplify migrations. Customers have made strong requests that they want stored procedures in Amazon Redshift, to make it easier to migrate their existing workloads from legacy, on-premises data warehouses. Amazon always works backwards from the customer’s needs.
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