The PL/SQL lock timer wait event represents the amount of time a user or application has “slept” through the USER_LOCK.SLEEP or DBMS_LOCK.SLEEP procedures. The ‘idle’ event “PL/SQL lock timer” is worth watching because it can indicate issues with application response, throughput and possibly coding. The PL/SQL lock timer wait event is, as the command that issues … Read more Oracle PL/SQL Lock Timer Wait Event

Description from The SentryOne community Why was a query plan not collected? SQL Sentry uses a complex algorithm to perform matching of cached execution plans from SQL Server to Top SQL events. This article describes some of the more common reasons that a match may not have been found for a specific batch or statement. … Read more SQL Server – Query plan was not collected

Description from The SentryOne community One of the things we’ve come to understand in our dealings with the Windows operating system as it relates to performance monitoring is that the performance counter system is very fragile. It doesn’t take much at all to set it off kilter and most of the time you won’t even … Read more Issues with Performance Counter Collection

SQL Server DBAs—even those who have years of experience with relational databases—frequently make the same mistakes repeatedly. Wouldn’t you like to learn about those blunders so that you can sidestep them? Well, I have good news! In a recent webinar, I counted down the 10 most common SQL Server mistakes DBAs make. Read below as I recap … Read more Top 10 SQL Server Mistakes Made by DBAs

One of the most fundamental concepts in any relational database management system (RDBMS), such as SQL Server, is the transaction. During my consulting career, I’ve seen many performance problems caused by developers not understanding how transactions work in SQL Server. In this tutorial, I’ll explain what transactions are, why they’re necessary, and how they work … Read more A Complete Introduction to SQL Server Transactions

You can use the CREATE TABLE statement to enforce several different kinds of constraints on a table: candidate keys, primary keys, foreign keys, and check conditions. A CONSTRAINT clause can constrain a single column or group of columns in a table. The point of these constraints is to get Oracle to do most of the work … Read more Defining Constraints within CREATE TABLE in Oracle 12c

One of the easier ways to improve the performance of your SQL Server and Azure SQL database queries is to ensure you choose the right data types for your data, and the data types in your application’s code match the ones in your stored procedures and queries. Choosing the right data type conserves space, because … Read more How Data Types and Query Tuning Can Improve Application Performance

Many organizations have migrated their environments from on-premises to the cloud, and one of the clouds of choice is Microsoft Azure. For SQL Server workloads, organizations can use platform as a service solutions with features like Azure SQL Database and Managed Instance or infrastructure as a service solutions with Azure SQL virtual machines. Azure SQL virtual … Read more How to Make SQL Server Faster on Azure VMs