Overuse of ad-hoc queries by applications is a common source of SQL Server performance problems. The symptoms include high CPU and memory pressure. Phil Factor offers a simple custom metric to monitor the percentage of ad-hoc queries being executed on a database, and shows how SQL Monitor can detect when the problem is happening, and show you the queries that are affecting the server. Read more
Chris Unwin explains the basic approaches to anonymizing email addresses, and shows how Data Masker can generate realistic email addresses, based on faked names, and even retain the correct distribution of email providers. Read more
Use of the read committed snapshot isolation level is often an effective way to alleviate blocking problems in SQL Server, without needing to rewrite the application. However, it can sometimes lead to tempdb contention. This article offers a small-scale solution (not suitable for use on large tables) to detect cases when tempdb contention is related to use of RCSI. Read more
SELECT…INTO is a useful shortcut for development work, especially for creating temporary tables. However, it no longer has a clear performance advantage and should be avoided in production code. It is better to use a CREATE TABLE statement, where you can specify constraints and datatypes in advance, making it less likely that inconsistencies will sneak into the data. Read more
How to qualify object names, standardize the use of aliases, and make other instant changes that improve the quality and performance of your SQL code. Read more
This article explains what SQL Server deadlocks are, why they occur, why they require immediate investigation, and the diagnostic data required to troubleshoot them. It then demonstrates an "Update Order" deadlock condition and shows how to find the cause quickly, in Redgate Monitor, using the Extended Events deadlock graph provided by the deadlock alert. Read more
Phil Factor demonstrates the performance problems that overuse of ad-hoc queries can cause and then how SQL Monitor can warn us when they are the cause of these problems on your SQL Servers, using built-in metrics such as SQL Compilations/sec metric and Batch Requests/sec. Read more
Phil Factor explains why you should prefer use of EXISTS over IN, when comparing data sets using a subquery. While there is no longer any significant performance advantage, using NOT EXISTS will avoid unexpected results when the subquery’s source data contains NULL values. Read more