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From:Øystein Grøvlen Date:February 11 2011 10:10am
Subject:Re: bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085
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On 02/11/11 11:00 AM, Jorgen Loland wrote:
>  >@@ -599,15 +604,17 @@ longlong Item_singlerow_subselect::val_i
>  >
>  > String *Item_singlerow_subselect::val_str(String *str)
>  > {
>  >+ DBUG_ENTER("Item_singlerow_subselect::val_str");
>  > if (!exec() && !value->null_value)
>  > {
>
> JL: The bug was that this code assumes that value->null_value will not
> change when value->val_* is called. As this bug shows, this is an
> incorrect assumption. I think that it's unsafe to assume anything about
> val->null_value before calling val_ in all Item_singlerow_subselect::val_*
> functions.

I think this is generally true for all Items.  One cannot rely on 
null_value being set until a val_xxx method has been called.
Good catch, Jørgen.

-- 
Øystein

> This is only a theory and remains to be tested. I send this
> concern without investigating thoroughly because we are in a hurry with
> this patch:)
Thread
bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085Tor Didriksen11 Feb
  • Re: bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085Øystein Grøvlen11 Feb
  • Re: bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085Jorgen Loland11 Feb
    • Re: bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085Øystein Grøvlen11 Feb
      • Re: bzr commit into mysql-5.5 branch (tor.didriksen:3323) Bug#60085Tor Didriksen11 Feb