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From:shyam gautam Date:April 7 2010 9:58am
Subject:table load in mysql
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hii  to all;


question:

let us suppose that we fire a query like select sum(salary) from
employee where salary < 54;

then according to me this steps is follows
1) storage engine select particular table employee and select the
particular colum according to the constraints
now this data is ready to computation means it ready to supply to the
microprocessar
2)now apply sum algorithm of mysql on that particular colum ( means those data)
microprocessar apply sum operation on that give the result
3) then display the result


basic question:

so if i am right that myquestion is that
what is particular class name or module which is doing the first step and how ;
means explain me with example that particular module or class load the
table with the requested colum means prepared the data which  is ready
for computation ( means sum operation according to my question) means
in which line of coding in that module data is prepared for
computation ( sum ) and how this data is transferred to cpu at the
code level for apply sum algorithms

 in my example here the data which is ready for sum opeartion is
salary colum in which salary is < 54
 how my sql use salay< 54 ( also explain it  at code level which
datastructure is responsible for this)

means if i want to transfer this loaded table with resquested colum
to the another memory unit of another cpu then what module or class
and function or datastructure is entry point for that second cpu
memory



2) so my question again is that how this sum operation is apply on
that means which class and function is responsible for this and how
i want to answer at code level implementation .

explain the sum operation with the datastructure use for this sum
operation at code level

3) when the sum is complete then which module or class and function
take the result from ram to display explain me at code level


please explain me only at the code level implementation means expalin
me the flow of code of my sql according to my question steps



thanks
Thread
table load in mysqlshyam gautam7 Apr