>>UPDATE table SET table.par = table.par + 1
>>WHERE table.key IN ('value1', 'value2', ... , 'value1200' )
>
>
> How fast is the query alone, i.e.
>
> SELECT * FROM table
> WHERE table.key IN ('value1', 'value2', ... , 'value1200' )
Also, post the output of '\d table' and EXPLAIN ANALYZE UPDATE...
Chris