Thread-Local Storage

Ewald Cress digs into fundamentals:

As a teaser for where this is heading, I’ll reframe the problem as classic SQL Server examples. Firstly, when a latch wait occurs somewhere in the bowels of a LatchBase subclass instance, how does that latch method know to track the wait against an instance of a Worker, or make it known to the world that it is holding up that Worker? And secondly, at a much higher abstraction level, when a task executes a user query and needs to access a table, how does the access methods code know what security principal to do security checks against? We are taking the first steps towards answering these questions here.

I enjoy Ewald’s explanations because when I’m done, I really feel like I have a clue of what’s going on.  It all fades away as soon as I look away from the screen, but that’s on me, not him.

Related Posts

Understanding Hash Match Aggregates

Itzik Ben-Gan continues his series on grouping and aggregating data by looking at the hash match aggregation process: The estimated CPU cost for the Hash Aggregate in the plan for Query 8 is 0.166344, and in Query 9 is 0.16903. It could be an interesting exercise to try and figure out exactly in what way […]

Read More

Row Width And Snapshot Isolation

Kendra Little shows us the impact that row width has on snapshot isolation: So I went to work to demonstrate row width impact on the version store — when only a tiny bit column is changed in the row. Here’s how I did the test: I created two tables, dbo.Narrow and dbo.Wide. They each each have a […]

Read More

Categories

May 2016
MTWTFSS
« Apr Jun »
 1
2345678
9101112131415
16171819202122
23242526272829
3031