SQL & PL/SQL

Hi,

The comparison is on basis of performance. There are billions of records to be processed and millions to be updated.

Please go through the folowing queried to have general idea because the actual query is 2 page long.

Update table1
set column=( select query)
where exists (select 1 from table2 where table2.item = table1.item)


Vs


Update table1
set column=( select query)
where (item) IN (select item from table2 )


Please give inputs in term of performance.

Both of these queried have same execution plan But I have worried about the hard parse and other parameters that can make huge difference in performance.

Regards
Nitin Bajaj