What Is Parallel Query?

You've probably heard that computers are fast. You've probably also heard that SQL queries could be slow. have you ever wondered why? The answer is: that they're doing things sequentially. When a computer executes a query, it must read through the entire table and return every row to get the desired results. This takes much time, especially if your data set is significant or your query is complex. There's a way to combine the two and make them go faster: parallel query! A parallel query is a method used to increase the execution speed of SQL queries by creating multiple query processes that divide the workload of a SQL statement and execute it in parallel or simultaneously. SQL has a long history, but it's still winning. If you've been around for a while, you've probably heard about the benefits of concurrency. Before the days of SQL, databases were usually one-at-a-time affairs. You'd submit your query and wait for it to run before introducing the next one. If you had multiple CPUs (rare), they would all be waiting for that first query to finish before they could start processing anything else. Then something magical happened: Parallel Query came along! Now, when you're writing SQL queries, you can have multiple processes running at once, and each procedure works on something different! This means that each CPU can work on its operations in parallel instead of waiting for everything else to finish. Parallel query processing is a great way to boost the performance of your SQL queries. It's when the server looks for query index operations that might benefit from being run in parallel. Then, it inserts exchange operators into the query execution plan to turn it into a parallel-query execution plan. This means that instead of using one thread or process for execution, you can have more than one!