SQL Queries and CPU usage
- Details
- Category: SQL
- Published: Thursday, 28 April 2016 22:35
- Written by Super User
- Hits: 1200
Many companies today that have invested in expensive hardware, and are running their applications and databases on it, are experiencing CPU constraints, either overall or at certain peak times in their application or database hosts or even both. In regarding of the database host then 70 % to 80 % of the cases it is due to poorly written SQL queries that are executed against the database either just once or multiple times. Many of these companies invest in bigger and faster hardware to solve the problem. However these investments can in most cases be skipped and the problem solved in a matter of minutes and/or much cheaper way using built in tools in the database or additional GUI tools that are either bought for a small license fee or even free of charge.
Solving CPU intensive SQL queries in cheaper way.
When building sql queries it becomes very crucial to build it in such way that the queries are as efficient as possible. Why ? It all comes down to performance. i.e the application performance. When an application runs a query against a database, either residing on the same host as the application or a different deticated database host, it consumes certain amount of CPU usage. This CPU usage can range from something under 1 % up to almost 100% of the CPU usage depending on data, table layout, database config but most of all how the query is written. A very badly written SQL query can put down a busy host in a matter of minutes or seconds in certain scenarios.