Albin Issac has a useful blog entry about improving Oracle SOA EM console performance in Oracle SOA 11g.
The last few weeks, our Oracle SOA EM performance deteriorated rapidly. Loading the process dashboard could take 10 minutes or more. I applied the settings as Albin suggested ( Right Click on SOA-INFRA in the EM console, go to SOA Administration->Common properties, check all boxes in Data Display Options).
You have to keep a couple of things in mind when setting a duration. Setting it to 1 hour does not only imply it shows the processes started in the last hour, but also calculates the instances count of the last hour. This cannot be overridden in the dashboard. If you would like a bigger timeframe, try to find a trade-off between performance and calculation interval. Because we have relatively few, but long-running instances (weeks to months), we chose a duration of 21 days.
The drawback is that older instances are not visible anymore. Chances are big these are the ones requiring extra scrutiny.
Fortunately, you can override the duration of the displayed instances in the Instances tab. The Start Time From parameter is prefilled with a date based on the duration. You can modify it and rerun the query. Instances started before the default duration are shown in the overview.