Databases Reference
In-Depth Information
So, what is SAP HANA?
SAP
is likely the largest computer software house in the world today. SAP is famous for
its
Enterprise Resource Planning
(
ERP
) software, used by most of the largest companies
throughout the world.
SAP's ERP system allows businesses to store just about all the information they need to
function, from data related to customers, to purchase orders, to deliveries, to invoices,
through to production schedules for factories, stock levels, and so on. SAP's main selling point
is the real-time, integrated aspect of the system—if an incoming delivery is entered into the
system, then the stock levels are updated in real time. Data is always fresh, always current.
In 1997, SAP released SAP
Business Information Warehouse
(
BIW
), its vision of a data warehouse
solution for the SAP ERP system. This product has gone through several different versions, right
up to the SAP
Business Warehouse
(
BW
) 7.3 version, the latest at the time of writing.
The SAP BW (Business Warehouse—the term used to describe the underlying technology,
as opposed to Business Intelligence, used to describe the user-facing technologies) system
allows users to report on the data stored in the ERP system, allowing anything from simple
analysis to complex simulations on sales forecasts depending on different factors.
The BW system usually does not use the same exact database machine as the ERP
system—data is moved from the ERP to the BW machine for reporting. This is done so as
not to impact the data entry (vital) functions with someone wanting a report on last year's
sales (which is less important). Hence, the data in BW (and in data warehouses in general)
is not always up-to-date. Data loads are generally done once per day, introducing a slight
delay in data freshness.
Note, then, the two different principal functions of SAP's software, as follows:
Ê
SAP ERP stores data in a database
Ê
SAP BW takes the data in the database, aggregates it, and presents totals and trends
to the user
As we can see, the two systems will produce different loads on the system, in terms of the
SQL used by the applications to "talk" to the database. The first will essentially be
INSERT
and
UPDATE
instructions, whereas the second will almost exclusively generate
SELECT
statements.
Traditionally, it has been very difficult to optimize SAP BW systems to provide satisfactory
performance for reporting. Reports taking minutes or even hours to execute are not unheard
of, despite optimization efforts including precalculation of aggregates, storing multiple copies
of data at different detail levels, and so on.
