The European Commission could decide to delay Oracle Corp's $7.4 billion acquisition of Sun Microsystems Inc with less than 48 hours to go before a deadline, two sources familiar with the situation said on Tuesday.

The commission antitrust authority is debating whether to approve the deal by Thursday's deadline, amid concern about Oracle getting its hands on Sun's MySQL database, the sources told Reuters.

If the commission decides to open an in-depth investigation of the matter, such a review could take as long as four months, according to commission rules.

That could put the world's No. 3 software maker, Oracle, months behind its original plan for closing the deal, giving rivals -- including Hewlett-Packard Co and International Business Machines Corp -- more time to poach hardware customers from Sun, the No. 4 maker of computer servers.

HP and IBM have been offering discounts and other incentives to woo Sun customers since Oracle agreed to buy Sun in April, playing up concerns that software maker Oracle might have trouble running a hardware maker.

Commission officials have yet to decide whether to conduct such an investigation, according to the sources.

Spokesmen for both Oracle and Sun declined to comment.

Oracle shares closed up 0.3 percent to $21.94 while Sun shares fell 0.9 percent to $9.20, both on Nasdaq.

UNCERTAINTY

U.S. antitrust authorities cleared the deal last week without conditions after initially delaying the decision on concerns about another issue -- licensing of Sun's Java software. U.S. officials did not publicly cite any concerns about the MySQL database.

Jefferies and Co analyst Ross MacMillan said he was not sure how Oracle's acquisition of MySQL would stifle competition in the $19 billion a year database market.

MacMillan estimates that Sun generates about $300 million in revenue from MySQL. Oracle brought in about $9.2 billion in database sales last year, according to market researcher Gartner.

Redwood City, California-based Oracle agreed to buy Sun in April after the collapse of weeks of talks between the struggling hardware maker and IBM.

The deal gives Oracle's outspoken billionaire CEO, Larry Ellison, an entree into the word of computer manufacturing as well as control of Sun's Java software, one of the world's most widely used computer languages, and the Solaris operating system for Unix servers.

Ellison has said he wants to build and sell Sun computers preloaded with Oracle software and also tweak Java software so that it is easier to use on smartphones and netbook computers.

(Editing by Edwin Chan, Phil Berlowitz)

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