Understand the scope and freshness of server data in SAP Control
Center.
Each server statistic presented in SAP Control Center has a scope:
- Delta – the number of occurrences since the last screen refresh.
For example, the user log cache statistics on the Transactions screen are delta
values.
- Rate – the number of occurrences over the given period of time.
Device I/O is given as a rate.
- Percentage or ratio – an amount, number, or rate stated as a
proportion to a whole. Percentage statistics include CPU utilization, space
usage on devices and segments, and cache hit rates. Ratios include cache
volatility.
- Count – a simple value; for example, the size of a database or
cache in megabytes, or the number of partitions in a cache.
- Cumulative – the number of occurrences since the server started,
or since the counter wrapped. On the Processes screen, you can set the Top 5
User Processes chart to display the five processes that use the most CPU, disk
I/O, or network resources as rates or as cumulative values.
Note: When a server has been running for a long time, its statistical
counters might wrap, which means they restart from zero. This most often affects
cumulative statistics. Information about when or how many times a counter has
wrapped is not available.
Most server statistics not otherwise labeled are presented as deltas
since the last screen refresh; rates, percentages, and cumulative numbers are labeled as
such.
SAP Control Center displays statistics promptly. However, there are
several factors that affect the freshness of the data on the screens:
- The screen refresh interval, which you can set on the Settings
screen.
- The collection repeat interval, which you can set in the
scheduler for each server collection
- Network latency.
For more information about interpreting server statistics, see:
-
Performance and Tuning Series: Improving Performance with
Statistical Analysis
-
Performance and Tuning Series: Monitoring Adaptive Server
with sp_sysmon
-
Performance and Tuning Series: Basics