slow update but have an index

Hi,

I have a table with no relations to other tables. It has a sequence
number field (integer) and a status field being a char.

There is a unique index on the seqno field.

Now this table has about 80,000 records. I need to update 74,000 status
fields. So I made a dump, and hacked the dump into SQL statements like:

update accounting set status = 'C' where seqno = 1566385;
....
and the other 74,000

This is awfully slow. How come ? The index on the seqno should give
speedy access to the record.

Thanks,

--
Feite Brekeveld
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