Sun developed the Java programming language and owns MySQL
Oracle boss Larry Ellison says his firm's takeover target is losing $100m (£61m) every month as it waits for the verdict of an EU probe into the deal.
The business software firm has proposed a $7.4bn takeover of computer hardware and software maker Sun Microsystems.
In August, the US Justice Department gave its approval to the deal, agreed between the two firms in April.
"The longer this takes, the more money Sun is going to lose," Mr Ellison told an audience in Silicon Valley.
However, he thinks the EU will eventually approve the deal.
"The US took their time and deliberations and cleared it," Mr Ellison said. "The Europeans have to do their job, but I think once they do their job, they'll come to the same conclusion."
The EU is concerned that the deal, if approved, could breach competition rules, leading to higher prices and less choice for customers.
It is concerned mainly about Oracle having control over Sun's MySQL database business.
EU Competition Commissioner Neelie Kroes has said the EU is obliged to investigate "when the world's biggest proprietary database company proposes to take over the world's leading open-source database company".
But Mr Ellison said that Oracle and MySQL did not compete against each other, and said he would not sell off MySQL to get the deal approved.
The EU has said it will make its final decision by 19 January.
Oracle is looking to strengthen its position against rival IBM, which abandoned its own attempts to buy Sun earlier this year.