MAIN MEMORY DATABASE

1
MAIN MEMORY DATABASE

• Definition
• Overview
• Advantages
• Disadvantages
• Recovery

2
Definition

• Main memory database is database that is kept on
  main memory(RAM).
• Backup copy is on a magnetic disk.

3
OVERVIEW

• MMDB technology is capable of applications
  requiring short response time and high throughput
  rates.
• It does not requires disk access.

4
Advantages

• Fast query execution.
• Improved performance time.
• No I/O during transaction processing.
• Fault tolerant.

5
Disadvantages

• RAM is volatile.
• Data in main memory is lost due to computer
  failure.
• Data is kept on main memory for long time,
  increase the chance of data lost due to failure.

6
RECOVERY

• Three aspects of recovery.
• 1.logging maintain a log of update activities.
• 2. checkpointing takes snapshot of DB
  periodically as backup.
• 3. reloading reloads backup to RAM.