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Removable Media
A better choice than you might think

MPbase often makes it possible to attain "hard-disk-like performance" with the use of less costly removable storage media. This allows the optional use of optical or, in some cases, even tape as the storage media for a database.

There are several aspects of MPbase that make it ideal for any database or data warehouse using fixed, removable, or mixed media. First, the process of naturalizing the data creates a segmented sequential internal layout. Second, by working with the file system directories, use of cache is maximized. Third, due to the parallel nature of MPbase the effects of wait times are minimized. Fourth, the compression both reduces the amount of data transferred and increases the speed at which the search executes.

The process of naturalizing data creates a productive layout for removable media. MPbase breaks the information up into lots of discrete files. These files are in groups such that one or two large blocks will tend to resolve most queries. The placement of data in the naturalized format tends to minimize the number of such blocks needed by any one query. And, MPbase at the same time reduces the number of disks or tapes needed by any single query.

The indexing is to a large degree resolved by the file system index. This index is almost always in a memory cache and is at least partially loaded during a mount. In the case of media management libraries, this information is normally kept on disk. This allows a very quick selection of the sections of the database that will need to be searched.

As the MPbase is massively parallel it can be working on many queries or sub-queries at the same time. This reduces the impact of media waits. With many parallel internal paths the searching of blocks already in memory occurs in parallel with the media waits for new blocks.

When added to the compression, which makes the system more CPU rather than I/O-bound, you create the best possible scenario for a database containing removable media. Keep in mind that this system is NOT a waster of CPU time. It reads the data smart, not hard. The structure of the naturalized data allows it to spend most of its time on useful work rather than on reading and parsing unnecessary data blocks.

Although each of the above will help with removable media, all of the above have a tremendous effect on the total throughput.

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