Convert TimeStamp to Date

Hi all,

I am trying to convert a timestamp field to a date. ('1993-08-10
17:48:41.074' to '1993-08-10').
I used date(TIMESTAMP_FIELD), but it seemed working only for date
after year 2000 and return the previous date
for any day before year 2000. Is that a bug or I just didn't
understand the function?

I am now using to_date(TIMESTAMP_FIELD,'YYYY-MM-DD'). It works but
the performance is very poor. My query is about
2-3 times slower now.

So, what is the most efficient way to cast a timestamp field to a
date?

Thank you for your time!

LS