Remove 2014 Remove Database Remove Hardware Remove Tuning
article thumbnail

The Speed of Time

Brendan Gregg

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you _time_ time?

Speed 126
article thumbnail

Finding Distinct Values Quickly

SQL Performance

Back in 2014, I wrote an article called Performance Tuning the Whole Query Plan. I will be using the 50GB Stack Overflow 2013 database , but any large table with a low number of distinct values would do. The Stack Overflow 2013 database comes without nonclustered indexes to minimize download time. Test Environment.

Servers 86
Insiders

Sign Up for our Newsletter

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Trending Sources

article thumbnail

Common SQL Server Mishaps

SQL Performance

This article will expand on my previous article and point out how these apply to SQL Server , Azure SQL Database , and Azure SQL Managed Instance. When looking at backups, I check for recovery model and the current history of backups for each database. Azure SQL Database and Azure Managed Instance have managed backups.

Servers 49
article thumbnail

The Speed of Time

Brendan Gregg

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you _time_ time?

Speed 40
article thumbnail

Understanding Execution Plan Operator Timings

SQL Performance

SQL Server 2014 SP2 and later produce runtime (“actual”) execution plans that can include elapsed time and CPU usage for each execution plan operator (see KB3170113 and this blog post by Pedro Lopes). This can make it difficult to draw sound performance-tuning conclusions. The clock keeps running at the same rate even during sleep.

Servers 95