This menu function shows information about the effectiveness of the ADABAS server's data buffering (caches). The ADABAS server keeps statistics on the current number of both physical and buffered read and write accesses.
Example:
The display contains the following information about the ADABAS caches:
- Total number of accesses (Accesses) as well as number of successful (Satisfied) and unsuccessful (Failed) accesses to the ADABAS data cache
- Percentage of successful accesses to the database data cache
(Hit rate %)
Analogous to the accesses to the ADABAS data cache, the values for the following caches are displayed:
- the file directory cache (File directory)
The database system uses this area for internal organization. For example, the page addresses of the roots of the individual data trees are administered there.
- the FBM cache (FBM Cache)
This area is used for the management of free disk blocks.
- the converter cache (Converter Cache)
- the USM cache (USM Cache)
This area is used for the User Storage Management.
- the log cache (Log)
During rollback, the log cache helps to accelerate the process.
- the dictionary cache (Catalog)
Information from the data dictionary of the database provided in the dictionary cache is available fast because no accesses to the disk are required. The hit rate for this area should therefore be more than 80%.
- number of accesses to the temporary data cache (Temporary)
Temporary result sets are managed in the temporary cache. Such result sets are created, e.g., during the execution of a SELECT statement with ORDER BY clause.