I wrote two posts about wait stats: What wait means About SQL Server saving wait stats on DMVs Now, going deeper on wait stats and see "why SQL Server is running slow?". To answer that question I like to start with the DMV sys.dm_os_wait_stats, because this DMV provides a running total of all waits encontered … Continue reading Using wait stats on SQL Server
Difference between Lock and Latch
Locks everywhere is a good start to understand how SQL Server provides logical consistency. Every operation has a lock and latch. What does Latch mean? Latch protects memory on Buffer Pool, is a method that provides physical consistency. SQL Server does operations in memory, that means, it read the page from disk and put that … Continue reading Difference between Lock and Latch
Wait Statistics
The first post about waits on SQL Server was regarding what SQL Server Wait means, a brief explanation and the concept might be difficult to catch at first. When the task needs to wait for a resource, it is placed on a list until the resource is available. SQL Server keeps detailed internal records of … Continue reading Wait Statistics
Wait wait wait…
Let's talk about why we have to wait and how to understand the wait types. Paul Randal in his post Wait statistics, or please tell me where it hurts said: A thread is using the CPU (called RUNNING) until it needs to wait for a resource. It then moves to an unordered list of threads … Continue reading Wait wait wait…
