Number of physical writes

Number of physical writes: <count>

Explanation

Not all of the data used by the applications can be held in the data cache. This causes pages from the data cache to be displaced to the data area, which means that there are a large number of writes to the data volumes.

This phenomenon is almost unavoidable if load times (data import) are long, since the imported data is usually much larger than the size of the data cache.

Also, a savepoint also writes modified pages from the data cache to the data area at regular intervals. Read and write activity increases significantly at this time, without causing a genuine bottleneck. In normal operations, you should not be able to measure any significant write activities other than the savepoints.

User Response

If you notice a high level of write activity in normal operations, first make sure that no savepoint was active during the measurement interval (which is possibly too short).

If no savepoint was active, increase the size of the data cache.