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From:Joseph Lukas Date:July 20 2009 5:10pm
Subject:Re: GSoC Week 11 - July 13 - July 19 | per query variable settings
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I am sorry in my second posting I noted I may have found a way and on
some of my errors.  I may have a way to accomplish it successfully if
I am unable to do so I will be contacting you to solve the issue.  I
will now later this week if it works at all.  I looked at the other
methods on how to set up the set_var and should be ok in doing it for
myself.  I am 70% confident I can do it and would like to try first.
Plus I don't have 2 hours to explain all the details in typing due to
some of the sizes and flipping between files for the examples I found
that may help.


On Mon, Jul 20, 2009 at 12:59 PM, Sergei Golubchik<serg@stripped> wrote:
> Hi, Joseph!
> On Jul 19, Joseph Lukas wrote:
>> Looking further into the set_var class structure as this will be key to
>> triggering all the proper reset functions for the variables.  I also
>> removed the additional system_variables struct from the THD.   Not much
>> actual code work as looking into more of the structures that make up
>> set_var.  It looks like the main part is the public variable value inside
>> set_var this is of type Item * which contains the values to be set.
>> Currently though it appears that the value inside the Item class is of type
>> String stored inside of str_value.  So far I assume this is where the value
>> is stored and is converted to the proper type later.  The idea is now that
> Not really.
> Check, for example, sys_max_prepared_stmt_count - it's
> sys_var_long_ptr_global, sys_var_long_ptr_global::check() calls
> get_unsigned(), which executes
>    var->save_result.ulonglong_value= (ulonglong)
> var->value->val_int();
> this calculates the value of the 'Item *value' directly as an integer,
> it's not stored as a string.
>> I find the associated current value before the change takes place I have to
>> convert it to a string and insert it into set_var's
>  var->value->str_value
>> since so far I do not see where the value is stored elsewhere inside of
>> set_var class.  If I am wrong please inform me where the value is stored
>> inside set_var class.
> No, you are not wrong. String values - for variables that store
> strings - are currently taken from var->value->str_value
> (incidentally, it's a bug, but let's assume this is how it should work :)
> Numeric values are obtained by calling var->value->val_int()
> (or ->val_real(), or val->decimal(), whatever appropriate).
>> Properly getting and resetting the variables to perform after update
>> functions.  I need to find where in set_var the value is stored.
> Why do you need to find it ? Can you just call ::value_ptr() and
> ::check()/::update() ?
>> I may have found it but I am not too sure as printing values stored
>> inside of the structures is a pain.  I am not used to performing print
>> operations on structures not using the C++ standard library and it is
>> frustrating. Many of the variable names I assume store what I think
>> but they are not very descriptive always in the code so I am only
>> making guesses.
> Want to chat on irc ?
> You could quickly get answers to your questions this way.
> You can find me on freenet, #mysql-dev channel.
>> None so far as I am back in the hole of getting the current setting
>> before changing it and putting it in the set_var structure to use the
>> update functions at the end to reset the variables to previous
>> settings.  This is my biggest roadblock and it has not gone well for
>> the past few weeks.
> let's try to solve it together on irc
>> I did not even know of the future plugin settings that are going to have to
>> be looked at.  That is on hold since I need to get past my current issue
>> before looking at the other.
> ok, let's do "normal" server variables first.
> Regards / Mit vielen Grüßen,
> Sergei
> --
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>  /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik
> <serg@stripped>
>  / /|_/ / // /\ \/ /_/ / /__  Principal Software Engineer/Server Architect
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GSoC Week 11 - July 13 - July 19 | per query variable settingsJoseph Lukas19 Jul
  • Re: GSoC Week 11 - July 13 - July 19 | per query variable settingsSergei Golubchik20 Jul
    • Re: GSoC Week 11 - July 13 - July 19 | per query variable settingsJoseph Lukas20 Jul