1. Thanks to our platinum sponsors :
Please add this slide add the start of your presentation after the first welcome slide
Intro (5 minutes)
Thank the sponsors
Why does it matter
Introduce yourself
Locks (10 minutes)
Why do we have locks?
How do they connect to the data-objects we have?
Data Structures (10 minutes)
What kind of data structures do we have?
NoLock Issues (5 minutes)
How does NoLock effect the way data is being read
Cascading Delete
Read NoLock Speed
Avoiding ( 10 minutes)
PASS SQL Saturday Holland

2. Thanks to our gold and silver sponsors :
Thank the sponsors
Thank the audience
Whom am I
PASS SQL Saturday Holland

3. Why this talk Different people, Different ideas.
Some people always want NoLock
Some people always want to avoid NoLock
Acid vs Base
My hope is to give you the backgroup information so you can have an opinion on NoLock.
Waarom dit onderwerp
Kort de agenda
Hoe werken locks in SQL
Hoe wordt data gelezen
Wat zijn manieren om locks te vermijden zonder NoLock.

4. What is a lock
A lock is on an object; which can be a table, a partition, a page, or a row.
Is, s, iu, u, ix, x etc etc

5. What is the process we will be seeing a lot during this talk.
A Query gets executed
First it creates an Intent Lock
When it gathers enough free Intent Locks, it tries to upgrade them to lock the resource
Then executes the query
To fake a state, or increase the duration we add an explicit transaction

6. 1.(S) locks are compatible with (S) and (U) locks.
2.(X) locks are incompatible with any other lock types
3.(U) locks are compatible with (S) but incompatible with (U)
Update locks worden gehouden tot ze data modificeren  excusive lock

7. DEMO
Quick_overview_locks

8. What did we just see?
Locks are designed to prevent you from reading unwanted results
Locks are in different types of heaviness and can co-exist!
Transactions influence locking behaviour
Quick_overview_locks

9. Isolation levels Serializable Repeatable Read Read Committed
No update/delete/insert
Repeatable Read
No Delete/Updates
Read Committed
You can change, I’ll just adept
Read Uncommitted
You are planning to do something? Let’s act on it.
Nolock breaks any isolation-level; it lets SQL believe it’s reading non-changing data.

10. What is a page-split

11. DEMO
Create_PageSplit
Cascading_Deletes

12. Page
SlotArray is de plek waar verteld wordt waar de data staat.

13. Two ways of accessing data

14. Adding data to a page

15. DEMO
Read_NoLock_Speed.sql
Quick Allocation

16. Recap A Data-row is the smallest entity.
There is a reference in each page and two ways of getting to the data.
Optionally template for your own slide

17. Possible solutions Determine your requirements. Avoid Lock escalation
Batch your queries / transactions
Snapshot Isolation (silver bullet)
Design Properly

18. Airplanes; if it’s in transition and you don’t get data back to the system.. It’s very very likely to be in the progress of being taken.
Thusly it doesn’t matter if we don’t read the data; we can assume what the outcome is.

19. Demo
Avoiding_Lock_Escalation (dirty)
AvoidingDeadlockByIndex

20. Please fill in the evaluation forms
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21. Used scripts