TDWI Hot Topic // In-Memory versus Optimizing for Memory Usage

May 31, 2013

When is an in-memory database not an in-memory database?

The “classic” definition is of a database that runs entirely in main (or physical) memory. In other words, if you have an “in-memory” data warehouse (DW) of 512 GB, all of your data and indexes must fit into 512 GB, which means you may run out of physical memory.

Many so-called “in-memory” databases don’t do this, however.

This isn’t so much a problem as a source of confusion. The classic in-memory database is constrained by several factors, not the least of which is the amount of physical memory available to the system. For this reason, some “in-memory” database engines actually use a kind of memory-optimized design. This means that the database tries to make intelligent decisions about which data to load into memory, how (or at what levels) it caches data, and how it performs certain kinds of operations.

READ MORE: Download this Hot Topic.

TDWI Membership

Get immediate access to training discounts, video library, BI Teams, Skills, Budget Report, and more

Individual, Student, & Team memberships available.