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What is the CXPACKET Wait Type?

This wait type indicates that parallel plans execute on the server. This wait type doesn’t necessarily means there is a problem. It only points to the existence of parallelism. In many systems, this wait type is very common, usually the top 1. The fact that it’s so common means there is a lot of parallelism. One of the reasons for having a lot of parallel plans is large scans. Scan operations are usually performed in parallel. By optimizing queries and/or adding the appropriate indexes, it is possible to reduce the number of scan operations and thus reduce parallelism in the system. In some cases a parallel plan does not execute efficiently, and reducing the max degree of parallelism might improve performance, but this is relatively rare. In most cases, if we reduce the max degree of parallelism, we will make things even worse, because now these large scans will have to be executed serially instead of in parallel. The right thing to do is to optimize the relevant queries in order to avoid the large scans in the first place.

The post What is the CXPACKET Wait Type? appeared first on Madeira Data Solutions.

Guy Glantser

Guy Glantser, Data Platform MVP, is the leader of the Israeli PASS chapter and also the CEO and founder of Madeira Data Solutions. His career has been focused on the Microsoft Data Platform for the past 20 years, performing various database roles as either an on-site DBA, an external consultant or a speaker. Guy is involved in many activities in the Microsoft Data Platform community. He occasionally speaks at community events, such as PASS Summit, SQLBits, SQL Saturdays and user groups around the world. He also co-hosts the SQL Server Radio podcast.


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