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 Displaying Cache Information 

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.

Prerequisites

The database instance is in the ONLINE operational state.

Procedure

Select the required database instance in the list of database instances. Choose Instance ® Information ® Caches.

Type

Cache type

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 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 and the general database parameter CACHE_SIZE must be adjusted accordingly.

 

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