Bad query performance after lots of updates

Hi, select count(*) from table where field = 'some value'; --> a few ms update table set field = 'value'; --> update 2 million rows out of 1 billion rows select count(*) from table where field = 'some value'; --> almost a minute :( Analyze did not help and sys.vacuum could not be used as the table has indexes (foreign key). Re-starting the DB helped ;) What's the recommended way to make MonetDB perform well after lots of updates? Kind regards, Daniel