You can say a lot of things about Larry Ellison, but never call him a quitter.

The planned merger of his Oracle (NASDAQ:ORCL) with Sun Microsystems (NASDAQ:JAVA) has been in regulatory limbo for months, leading some observers to speculate that Oracle might give up on the buyout altogether. But the deal is not quite dead yet. Oracle just received an extension on a deadline to tell European Commission investigators more about the deal, perhaps buying Oracle enough time to finally push Sun through the cobwebs of bureaucracy.

It's not the first time Oracle has gotten hung up on the way to a multibillion-dollar deal. The $10.3 billion PeopleSoft buyout took more than a year of courting, back-and-forth, and legal disputes. The BEA Systems deal, only slightly smaller at $8.5 billion, met with fewer regulatory challenges but featured plenty of price haggling, and it took just as long to complete as the PeopleSoft buyout.

The $7.4 billion Sun agreement is a strange beast that could turn Oracle into a Mini-Me version of IBM (NYSE:IBM). Oracle's traditional strength is in enterprise software such as large-scale databases, where the main competition comes from the likes of IBM, SAP (NYSE:SAP), and Microsoft (NASDAQ:MSFT). Sun will add some fresh blood to that sector, but it also makes Oracle into a major server vendor. That's another IBM stronghold, but also the domain of hardware specialists like Hewlett-Packard (NYSE:HPQ) and EMC (NYSE:EMC) in storage.

The Sun deal puts Oracle's finger into many new pies and places the company in direct competition with many of its biggest partners and customers. I still don't think it's a very good idea to do this, but Ellison seems determined to make it happen. And judging by his track record of making difficult buyouts a reality, I suppose this one also will come through in the end.