Under what circumtances, termsEnum's next(), or seekExact(), o seekCeli() is more efficient?

[hao yan]

Hey, guys

Two questions:
1.  From our experiments, we find next() is very costly. In TermsEnum's
javadoc,  it said that
TermsEnum is unpositioned when you first obtain it and you must
successfully call next or one of seek* methods. From my experiments, I find
that next() is costly.

My question is:

Can we only use seekExact() and never use seekCeil or next , in order to
improve performance ?

thanks!

hao