DBLinks have the reputation of being slow and therefore suitable only for occasional use, not for regular transaction processing.
However, I would not like to base the decision on whether to use or not use DBLinks purely on general reputation. What would be ideal would be to have concrete 10046 Oracle Extended Trace Data detailing for some particular query or set of queries exactly what percentage of response time is taken up by 'Message From DBLink' or anything DBLink related. (I am referring to the Resource Profiles outlined in Cary Milsap's book Oracle Performance.)
Does anyone out there have any such Extended Trace Data producing any information at all about the slowness of DBLinks? Does anyone have any hard data of any kind regarding DBLink performance?
And if hard data of any kind is lacking, does anyone have any based-on-experience guidance on when to use and when not to use DBLinks?