Grab a pen and notepad, and jot down your answers as you go, then check your answers at the key at the bottom of the page.
Questions
Q1. For a SELECT query running under read committed, locks are held….
- For the duration of the statement
- For the duration of the transaction
- For a very short time
- Until the Deadlock Monitor wakes up
Q2. SELECT queries running under read committed like to use….
- Exclusive locks
- Key range locks
- Shared locks
- Schema modification locks
Q3. Queries running under read committed may read the same row multiple times.
- True
- False
Q4. Queries running under read committed may miss some rows and not read them at all.
- True
- False
Q5. Queries running under read committed always use row level locks.
- True
- False
Q6. Fill in the blank: Read committed is a transaction ______ level in SQL Server.
Q7. Read committed is the default isolation level in SQL Server, EXCEPT in…
- Azure SQL Database
- SQL Server Failover Cluster Instances
- SQL Server RDS (Amazon)
- On-premises SQL Server installations
Scroll down for the answer key :point_down:
Answer Key
- A1. 3. For a very short time
- A2. 3. Shared locks
- A3. 1. True
- A4. 1. True
- A5. 2. False. The engine may decide to start with a page level lock, and lock escalation is possible as well.
- A6. isolation
- A7. 1. Azure SQL Database. Note: there’s an additional correct answer not in this list, which is readable secondaries in Availability Groups! Check out the course on Snapshot Isolation Against Readable Secondaries for more information on that.