Different statistics based on time range

caslett

On the Analysis page I'm getting different graphs and statistics for the Transactions/sec perfmon for a historical time range depending on the length of the range.

For example, if I view data for the last 7 days the graph shows a spike on 2/9/2011 9:23:25PM of 113.5.

If I create a custom range from 2/9/2011 20:00 to 2/9/2011 21:30 the spike disappears and the data within that time range shows a peak of 11.6 at 9:24:24.

If I shrink the range to 2/9/2011 21:00 to 2/9/2011 21:30 the data shows 10.8 at 9:24:24.

priyasinha

Hi,

Thanks for your post.

SQL Monitor plots a maximum of 50 data points on each graph and draws straight lines between consecutive points. For short time ranges (less than 10 minutes) the graph displays every data point. For longer time ranges, some of the data points cannot be plotted, so these graphs may provide a high-level overview of changes in values.

Data points are also plotted differently depending on whether counter values are derived from raw data or calculations.

For example, to work out Transactions/sec, the number of transactions between data points is divided by the number of seconds between data points. This averaging has the effect of smoothing out fluctuations.

Hope this helps.

Thanks,
Priya

blazdax

Hi,

I also noticed this and I have to say it's quite inconvenient not knowing whether you should drill in to a shorter time range or not. You either lose time doing it unnecessarily or you lose information not doing it when you should.

Any plans for changing the way plotting works?

Thanks

priyasinha

Hi,

Thanks for your feedback.

Yes, we are planning to make improvements to this. We are tracking this as SRP-3030.

Regards,
Priya