Oracle Warehouse Horizontal Partitioning
Oracle Tips by Burleson Consulting
The Data Warehouse Development Life Cycle
Oracle Features for the Data Warehouse
Read-only tablespaces in the real world
For a production Oracle data warehouse it is very important to
develop a method for determining when the data becomes permanent.
For example, a large data warehouse may store historical data for
the past decade, but the last 18 month’s worth of data are subject
to updates as the data status changes within the OLTP database. In
Figure 8.14 we assume that our fact tables have been horizontally
partitioned, that is, a very long table with rows going back ten
years in time will be separated into tables that govern a smaller
period of time.
Figure 8.14 - Horizontal partitioning of an Oracle warehouse
Here we see that the main fact table has been logically partitioned
into ten horizontal partitions, and only the most recent section of
the table (fact_97) is subject to update. The other partitions for
the fact table are static and will never change. For details of
using horizontal table partitioning with Oracle tables, see Chapter
4, Oracle Data Warehouse Design. For details on automatic table and
index partitioning with Oracle8, see Chapter 14, Oracle8 for the
We should also note that each chunk of the fact table has been
segregated into its own tablespace, such that there are ten
independent tablespaces for each table. We should also note that
this is a rolling strategy. As fact_96 ages into the static
category, the Oracle DBA will reorganize this table chunk to tightly
pack it into a static tablespace. This is achieved by calculating
the precise amount of storage for the table, and using Oracle
export-import utility to offload the data and pack it into the new
chunk . The index for each chunk also reside in its own tablespace,
and this is also packed into its new, static tablespace.
This is an excerpt from "High Performance
Data Warehousing", copyright 1997.
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