Re: [cx-oracle-users] prepare not needed before execute many, right?

[Amaury F. d'A. <ama...@gm...>]

2007/1/18, Mark Harrison <mh...@pi...>:
> Is there a difference between calling:
>
>      curs.prepare("call set_x1(:a,:b)")
>      curs.executemany("call set_x1(:a,:b)", mylist)
>
> and just:
>
>      curs.executemany("call set_x1(:a,:b)", mylist)
>
> I know it doesn't make sense, but my test program
> seems to be faster with the prepare.  I'm sure it's
> other factors, but I just want to make sure I'm
> not being stupid.
>

I checked with the cx_Oracle source code, and you seem to be right:
at the C level, there is no difference between the two cases.
Moreover, the additional function call should make the first sample a
little slower.

BTW, when the statement is prepared, it's better to call executemany
with None instead of repeating the query:
    cursor.executemany(None, mylist)
cx_Oracle compare queries by string identity ('is', not '=='). Here
the compiler optimizes the script by sharing the same string for the
two lines. So it should not have any performance impact in this case.

-- 
Amaury Forgeot d'Arc