Parse phase of sql statement Oracle and TOAD

Is it only the explain plan to look in when tuning a large sql string? Because when I push Ctrl+E in TOAD for Oracle (which generates explain plan), this takes several seconds. D开发者_Go百科oes TOAD do anything more than generating the explain plan, or is it really so that the parse phase takes 2-3 seconds for that specific sql statement?

I really can't see how to optimize the sql string anymore when looking at the explain plan. So I thought maybe there is something going on BEFORE executing the plan?

thanks in advance Martin (newbie oracle tuning expert)

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The explain plan doesn't tell you everything - Oracle just tells you an estimate of the costs of your query.
To get the real costs of your query, you have to actually execute it and check the performance afterwards (e.g. using tkprof).
I'd recommend checking out Asktom, e.g.
http://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:8764517459743
and getting a good book on Oracle performance tuning (e.g. "Effective Oracle by Design" by Tom Kyte).