Filter
Top Products
Optimization information
Information that is the basis for optimization in SymfoWARE/RDB. Optimization information includes the amount of
base table data (number of rows), the number of levels of indexes, and the number of different key values.
SymfoWARE/RDB integrates and evaluates SQL statements and optimization information and determines the most
efficient data manipulation processing procedures. Optimization information is collected using the rdbups command.
Overflow part
A constituent element of a storage structure unique to a RANDOM structure. When storage data can not be collected
in prime part pages because of excess data, the overflow part provides reserved pages for storing the excess data.
The overflows part consists of these reserved pages.
Related terms:
Prime part
Overflow pointer
When storage data is not collected in the prime part, the storage data is collected in the pages of the overflow part.
(This condition does not apply to a page split.) When this condition occurs, an overflow pointer connects the relevant
page of the prime part to the relevant page of the overflow part. The overflow pointer is unique to RANDOM structures.
Related terms:
Overflow part, prime part
Page
The smallest unit of I-O for a database. The size of a page is determined by the number of rows to store in the page.
Page split
A self-adjustment function unique to B-tree structures. When the amount of data stored in a given page exceeds a
fixed value, this function relocates storage data between separate pages (including empty pages). This relocation
evens the amount of data stored in pages to maintain a balance in processing efficiency.
Related terms:
B-tree structure
Parallel query
To raise the information processing efficiency in handling a large volume of data, a database is divided into several
DSI units. The parallel processing of DSI units is called parallel query processing.
Physical structure
One of the database structures along with the logical structure and storage structure. The database space located on
a magnetic disk volume is called the physical structure. A database space is an aggregate of fixed-size blocks.
Related terms:
Storage structure, logical structure
209