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From:Joseph Lukas Date:August 16 2009 4:26am
Subject:Re: EXECUTE and PREPARE - last minute issue
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I think I managed to fix the issue. I uploaded the code it is a little  
sloppy yet but it is late where I am at and required a large rewrite  
of some sections.  I will go over it more tomorrow as it is 12:30 am  
now.   I will also check the rest of my tests against the new code  
tomorrow as well.   I am looking into the type ulonglong and seeing  
what SHOW type it returns unless it is simply longlong which is  


On Aug 15, 2009, at 6:28 PM, Joseph Lukas wrote:

> I am having last minute issues with these 2 statements.   I have  
> spent most of the day looking at the issue but have not had any luck  
> solving it.  If the prepared statements contain a SET STATEMENT they  
> will work fine.
> However when you put something like SET STATEMENT var1 = X FOR  
> EXECUTE mystatement1;  I get errors/crash.  After working on it for  
> most of the day I have determined that the error is caused by the  
> Items being removed.  The pointers become invalid and forces a  
> crash. The set_var, and sys_var's both stay valid from my set_var  
> list used by the reset function only the Items containing the values  
> disappear.
> It works up until the reset function is called. The function goes to  
> var->check and crashes.  The code you have is fine to get the same  
> error. if you comment out DBUG_ASSERT(thd->free_list == NULL); in  
> sql_prepare line 3387. I bypassed it with an if(!thd->lex- 
> >stmt_set_list.is_empty()). In code on launchpad.
> I have been looking at ways around this but all Items in order for  
> clean up seem to be pushed into the thd->free_list.
> I have yet to figure out why or exactly where they are all deleted  
> or dropped as I even moved them out of the thd->lex and into a  
> structure in sql_parse.
> This is the only issue I have I am less worried on having SET  
> EXECUTE could be possible and should be.  I cannot figure out why/ 
> where the Items are being deleted.
> If I remove the reset function the remainder works as it should and  
> sets the variables and builds the structures to reset.  I even re- 
> did the function as to reset the variables after setting them to  
> make sure it was caused after the SQLCOM_EXECUTE functions.
> I am finishing some of the code cleanup and at least writing the  
> tests.  The only ones I have left to test for are the ones dealing  
> with EXECUTE.
> Like I said the PREPARE statements seem to work fine when the SET  
> STATEMENT is in the prepared statement like
> PREPARE stmt1 FROM 'SET STATEMENT sort_buffer=1000000 FOR SELECT *  
> FROM test';
> I pushed most current code as well to launchpad.  I have to finish  
> SHOW_DOUBLE a few comments and have about 5 more tests to write then  
> I can come back to this.  I have been about 10 hours at this trying  
> various methods but have other sections to finish.
> Joe

EXECUTE and PREPARE - last minute issueJoseph Lukas16 Aug
  • Re: EXECUTE and PREPARE - last minute issueJoseph Lukas16 Aug
  • re: EXECUTE and PREPARE - last minute issueMichael Widenius16 Aug