Oracle 64-bit Option Oracle Tips by Burleson Consulting

The Data Warehouse Development Life Cycle

Oracle Features for the Data Warehouse

Oracle’s 64-bit option - A look into the future

For very large data warehouses where sub-second response time is critical, few database engines can beat the performance of Oracle with the 64-bit option. Designed for use with Digital Equipment Corporation Alpha series (DEC-Alpha), Oracle’s 64-bit architecture performs more than 1000 times faster than standard Oracle 7 software. It is interesting to note that the DEC-alpha family of 64-bit processors has been around since 1991, and the database vendors are only now beginning to realize their potential for data warehousing. Since all of the major hardware vendors are creating 64 bit systems, let's t6ake a look into the future by examining the existing state of Oracle’s 64-bit option for data warehousing.

SQL complexity and response time

As we are aware, when Oracle performs n-way joins of a very large fact table against dimension tables, Oracle will denigrate in performance as the number of joined tables increases. (Figure 8.16) However, using Oracle' star query hints with bit databases, Oracle claims that queries will actually improve their response time as the complexity of a SQL query increases. In an Oracle study a DEC-Alpha with Oracle's 64-bit option showed response time improving as the number of joined tables increased.

Figure 8.16 An Oracle benchmark

As we may know, Oracle star queries maps the selection criteria conditions from the query and creates a cross-product of the dimension tables. This cross-product is then compared to the fact table by using a multi-key index into the fact table. For more information on star query hints, see the indexing section in this chapter.

Using a large SGA configuration with Oracle 64 on a DEC-Alpha, Oracle corporation demonstrated that a query that took more than one hour on a UNIX Oracle database ran in less than three seconds on a 64-bit processor with a STAR schema and six gigabytes of data buffer.

Figure 8.17 Query speed comparison, 32 bit versus 64-bit processors

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This is an excerpt from "High Performance Data Warehousing", copyright 1997.

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