Indexes are not a good thing… A blog on TCO

In many of my posts I refer to the issues associated with building “extra” data structures to meet performance goals (see one of my first posts ever here). These extra structures are always a trade-off… slowing the performance of one function in order to speed up another. I thought that it might be helpful to be…

SQLFire, Exalytics, TimesTen, and HANA… a quick comparison

As you may have noticed I’m looking at in-memory databases (IMDB) these days… Here are some quick architectural observations on VMWare‘s SQLFire, Oracle’s Exalytics and TimesTen offerings, and SAP HANA. It is worth noting up front that I am looking to see how these products might be used to build a generalized data mart or…

OLAP is not advanced analytics

OLAP searches a set of pre-aggregated data… a cube. If the cube is large enough that you don’t bump into the edges you might think that your search is ad hoc… but that is an illusion. The set is prescribed not ad hoc. In the 1980′s we sent paper reports out… they were moved on…

Cloud Computing and Data Warehousing: Part 4 – IMDB Data Warehouse in a Cloud

In the previous blogs on this topic (Part 1, Part 2, Part 3) I suggested that: Shared-nothing is required for an EDW, An EDW is not usually under-utilized, There are difficulties in re-distributing sharded, shared-nothing data to provide elasticity, and A SAN cannot provide the same IO bandwidth per server as JBOD… nor hit the…

More on Exalytics Capacity…

I found myself wondering where did the rule-of-thumb for Exalytics  that suggests that TimesTen can use 800GB of a 1TB memory space… and requires 400GB of that space for work tables leaving room for 400GB of user data… come from (it is quoted everywhere… here is an example… see question #13). Sure enough, this rule…