Added Readme
This commit is contained in:
parent
137f21f3d0
commit
c2ed485d65
58
README.MD
Normal file
58
README.MD
Normal file
@ -0,0 +1,58 @@
|
||||
# Purpose
|
||||
This repostiory contains examples which might be used to show/explain why and when deadlocks happen in MSSQL.
|
||||
|
||||
# How to
|
||||
1. Open two different SQL sessions.
|
||||
2. In each session open one file.
|
||||
3. Run SQL commands according to comments.
|
||||
|
||||
For example - running Read Commited should look like:
|
||||
|
||||
### Session 1
|
||||
```sql
|
||||
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
|
||||
|
||||
BEGIN TRANSACTION
|
||||
UPDATE Wycieczki
|
||||
SET cena = cena*2
|
||||
WHERE
|
||||
kraj = 'Bangkok'
|
||||
-- STEP 1 RUN ABOVE
|
||||
```
|
||||
|
||||
|
||||
### Session 2
|
||||
```sql
|
||||
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
|
||||
|
||||
BEGIN TRANSACTION
|
||||
UPDATE Bilety
|
||||
SET cena = cena * 2
|
||||
WHERE
|
||||
kraj = 'Ateny'
|
||||
-- STEP 2 - RUN ABOVE
|
||||
```
|
||||
|
||||
### Session 1
|
||||
```sql
|
||||
SELECT
|
||||
*
|
||||
FROM
|
||||
Bilety
|
||||
WHERE
|
||||
kraj = 'Ateny'
|
||||
-- STEP 3 RUN BETWEEN 1 AND 3
|
||||
COMMIT TRANSACTION -- COMMIT AFTER DEADLOCK HAPPENS
|
||||
```
|
||||
|
||||
### Session 2
|
||||
```sql
|
||||
SELECT
|
||||
*
|
||||
FROM
|
||||
Wycieczki
|
||||
WHERE
|
||||
kraj = 'Bangkok'
|
||||
-- STEP 4 RUN BETWEEN 2 AND 4
|
||||
COMMIT TRANSACTION -- COMMIT AFTER DEADLOCK HAPPENS
|
||||
```
|
Loading…
Reference in New Issue
Block a user