May 2022
Intermediate to advanced
497 pages
13h 4m
English
Content preview from SQL Server Advanced Troubleshooting and Performance Tuning
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Appendix A. Wait Types
This appendix provides a list of the most common wait types you’ll encounter during troubleshooting. It outlines conditions when the waits may occur and gives you some tips on high-level troubleshooting strategy.
Do not consider this appendix to be a replacement for the Microsoft documentation or the SQLSkills Wait Types Library. Nevertheless, it should work as good reference material within the book.
ASYNC_IO_COMPLETION
The ASYNC_IO_COMPLETION wait occurs during asynchronous I/O operations not related to the buffer pool. Common cases include:
-
Regular checkpoint
-
Internal checkpoint when you start a database backup or run
DBCC CHECKDB -
Reading GAM pages from data files
-
Reading data pages from the database during a database backup (unfortunately, this tends to skew the average wait time, making it harder to analyze)
A noticeable percentage of ASYNC_IO_COMPLETION waits may indicate an overloaded I/O subsystem, especially when it is present with other I/O-related waits. Perform I/O system troubleshooting (see PAGEIOLATCH waits later in this appendix).
See Chapter 3 for additional details.
ASYNC_NETWORK_IO
The ASYNC_NETWORK_IO wait occurs when SQL Server waits for a client to consume data. Three common cases may trigger this wait:
-
A slow network, often when clients are connected to the database server in another datacenter or in the cloud
-
Client applications running in under-provisioned virtual machines (VMs) or on overloaded servers
-
Incorrect ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.