Oracle Exadata vs IBM Power Systems

Cost comparison for business decision-makers between Oracle Exadata and IBM power system

The FactPoint Group is a Silicon Valley-based research, and consulting firm that is dedicated to the business improvement of its clients.Factpoint Group has conducted survey for Exadata vs IBM Power system with the help of customers as well as technical team who are using these systems.

The research produce TCO comparison for both the systems which includes:

• Acquisition costs
• Implementation and deployment costs
• Operations and maintenance costs for three years.

Below are the major points which were included in the research.

Implementation Cost

As per  research Oracle Exadata require 59% fewer man-hours than the traditional IBM system.

Implementation Time

Implementation of Exadata can be completed within one week where IBM system requires 3 week for implementation.

Operation and Maintenance labor

Exadata Storage Index Part-1

• It is not like traditional index which is in database. This is the feature of storage software and useful to eliminate IOs.
• Storage Index filter out data from the consideration. 

• It works by storing minimum and maximum column values for disk storage units, which are 1 Megabyte (MB) by default.
• Because SQL predicates are passed to the storage servers when Smart Scans are performed, the storage software can check the predicates against the Storage Index metadata (maximum and minimum values) before doing the requested I/O.

• Any storage region that cannot possibly have a matching row is skipped.

• There are no tuning technique or documents for storage index as it maintain by storage software only.

Storage Indexes consist of a minimum and a maximum value for up to eight columns. This structure is maintained for 1MB chunks of storage (storage regions). Storage Indexes are stored in memory only and are never written to disk.

Storage index is not static, whenever we shutdown or reboot storage server it will be removed and once server comes up storage server automatically create index.

Now we will see that how storage index actually work while executing the query on the DB server.

Click on image to enlarge.

Now we are executing below query on this table.

SQL> select * from TABLE where c>7;

In this case first query will go to the storage index and it will check min and max number for rows of first set but 7 is not fitting in Min and Max for rows of first set so, it will eliminate to check the data of that rows and it will move to second set of rows. 

Storage Indexes

-Storage Indexes provide the third level of optimization for Smart Scans. 

-Storage Indexes are in-memory structures on the storage cells that maintain a maximum and minimum value for each 1MB disk storage unit, for up to eight columns of a table. -Storage Indexes are a little different than most Smart Scan optimizations. 

-The goal of Storage Indexes is not to reduce the amount of data being transferred back to the database tier. In fact, whether they are used on a given query or not, the amount of data returned to the database tier remains constant. 

-On the contrary, Storage Indexes are designed to eliminate time spent reading data from disk on the storage servers themselves. Think of this feature as a  pre-filter.

-Since Smart Scans pass the query predicates to the storage servers, and Storage Indexes contain a map of values in each 1MB storage region, any region that can’t possibly contain a matching row can be eliminated without ever being read. 

-You can also think of Storage Indexes as an alternate partitioning mechanism. Disk I/O is eliminated in analogous fashion to partition elimination. If a partition can’t contain any records of interest, the partition’s blocks will not be read. 

-Similarly, if a storage region cannot contain any records of interest, that storage region need not be read. Storage Indexes cannot be used in all cases, and there is little that can be done to affect when or how they are used. But in the right situations, the results from this optimization technique can be astounding.