Displaying Cache Information
Use
The hit rates for the
caches show whether they were configured to be sufficiently large. The hit rates for the data cache and the converter cache are particularly important.
Procedure
Choose Instance ® Information ® Caches.
|
Name |
Cache name |
|
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 data cache hit rate should be at least 99% and the converter cache 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 repeated table scans are being performed and the table does not fit into 10% of the data cache.
If the values are permanently lower than the recommended percentage, this is a sign of poor performance and the settings of the database parameters DATA_CACHE and/or CONVERTER_CACHE must be increased.