You can display the hit rate of the caches in the Database Manager GUI. These hit rates show you whether the caches have been configured with enough space. The hit rates for the data cache and the converter are particularly important.
The database instance is in the ONLINE operational state.
...
1.
Select the required
database instance in the list of database
instances.
Connect to the
DBM server for this database instance if necessary.
2. Choose Instance ® Information ® Caches.
3. The following information is displayed for the different caches:
Accesses |
Total number of accesses |
Successful |
Number of successful accesses |
Unsuccessful |
Number of unsuccessful accesses |
Hit Rate (%) |
Hit rate (number of hits as a percentage of the total number of accesses).
|
The current values of certain database parameters that can affect the caches are also displayed.
The hit rate of the data cache should be at least 99% and the converter hit rate should be at least 98%.
Lower hit rates can
occur for a short time, for example when tables are read for the first time,
or when the table does not fit into 10% of the data cache in the case of
repeated table scans. If the values are permanently lower than the recommended
percentage, this is a sign of poor performance. In this case, the CACHE_SIZE
general
database parameter must be adjusted accordingly.