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