Download InMemoryDataBases(IMDB)

In Memory
Databases(IMDB)
Venkatesh (MT15016)
Kapish
(MT15026)
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,TerracottaBigMemory,voltDB,facebook-Scuba,SAPHANA
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

Motivation Behind IMDBs(2/4)
CPU addressable Size
Motivation Behind IMDBs(3/4)
Number of Cores/CPU are increasing
significantly, every year.
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
How do they work ?
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.
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.
