Regulators in Europe and the U.S. are taking a closer look at a recent policy change by Google that allows the search giant, in some cases, to blend data from different services and offer more targeted advertising.
According to the Wall Street Journal, the investigation has been prodded in part by one of Google’s rivals, Oracle (orcl), which presented slide shows to regulators with the title “Super Profiles Now a Reality.”
The controversy turns on Google’s announcement last year that it would begin combining data in new ways. For instance, a user’s browser activity on Chrome might be combined with her general search history and Gmail data, and all that might in turn be coupled with location data from Google Maps and other apps.
Google announced the new policy last June, and it went into effect in October. But—crucially—it is opt-in for existing users. The default for new users, however, is for Google to put them into the blended regime.
If you’re a Google user who wants to check if the blended data feature is on, go to your account settings (through Gmail or another of the company’s services), and then go to “Manage My Activity” and then “Activity Controls.” You should see a control panel like this one which will show if the blended data settings are on or off.
In a statement, Google (googl) pointed out the changes are optional and intended to give users more control over their data, and also suggested its rival’s privacy complaints are hypocritical. (Oracle owns giant data brokers like BlueKai).
AppDynamics, a so-called unicorn startup with a valuation of over $1 billion dollars, filed to go public in December and planned to trade on Nasdaq. (Although those plans have changed now that Cisco (csco) is buying AppDynamics for $3.7 billion.) Companies like Nike and Kraft use AppDynamics’s technology to monitor how their software and apps are operating.
Get Data Sheet, Fortune’s technology newsletter.
“Oracle claims to be the world’s largest audience data marketplace, so it knows how competitive digital advertising is. Its complaints, and those of its proxies, are frivolous,” said a Google spokesperson.
The Journal report says the regulatory investigation into the Google changes also extend to the U.S. Federal Trade Commission, though that may not be significant. The agency, which does not discuss active investigations, pursues hundreds of such inquiries every year and only a small percentage of those result in disciplinary action.
The pressure on Google is likely to be more intense in Europe where data protection rules are stricter, and where the search giant is already embroiled in a long-running antitrust fight with regulators.