1. In Memory Databases(IMDB)
Venkatesh (MT15016)
Kapish (MT15026)

2. What are IMDBs ?
A database management system that stores data entirely in main memory.
This is different from traditional on-disk Databases where data reside on secondary storage.
Example:IBM-dashDB,Terracotta- BigMemory,voltDB,facebook-Scuba,SAP- HANA

3. Motivation Behind IMDBs(1/4)
The motivation behind IMDBs is to have fast data access ,storage and manipulation by leveraging the positive trends in main memory and CPU technology.
Important Applications are :
 IP network routing
 telecom switching
industrial control
music databases in MP3 players
handle programming data in set-top boxes

4. Motivation Behind IMDBs(2/4)
CPU addressable Size

5. Motivation Behind IMDBs(3/4)
Number of Cores/CPU are increasing significantly, every year.

6. Motivation Behind IMDBs(4/4)
Cost of RAM Chip per byte is decreasing significantly over the years.
Cost of One GigaByte RAM chip will be $ .0001

7. How do they work ?

8. Limitation
IMDBs lack durability property as they  lose all stored information when the device loses power or is reset.
 Durability can be added to IMDBs via the following mechanisms:
Snapshot files, or, checkpoint images, which record the state of the database after particular time interval.
Transaction logging, which records changes to the database in a journal file and facilitates automatic recovery of an in-memory database.
Using Non-volatile random access memory (NVRAM), or an electrically erasable programmable ROM (EEPROM), the re-booting IMDB system can recover the data store from its last consistent state.

9. Conclusion
Since In-memory databases operate based on volatile memory and there is a limit on database size, so hybrid version of in memory databases (in-memory + on disk)are used.
If database size is small, then in-memory databases are the best choice.

10. THANK YOU