Breakpoint is responsible to stop execution of package when specific event occur in control flow to investigate and troubleshoot the state of the SSIS package.
There are 10 events in control flow
OnPreExecute: This event is raised by task or container certainly before it run
OnPostExecute: this event raised immediately after execution of logic of task completed.
OnError: This event raised when an error occur in task or in container.
OnWarning: This event is raised when task or container in a state does not justify the an error but show as a warning.
OnInformation: Basically this is called when task or container need to provide information.
OnTaskFailed: this event raised when it task fails.
OnProgress: This is called and show update when task logic executed.
OnQueryCancel : This called when executing task has been cancelled.
OnVariableValueChanged: This event raised by Integration Service runtime when value of a variable change. The RaiseChangeEvent of the variable must be set true to raise this event.
OnCustomEvent: This event raised by tasks to raise custom task-defined events.
To implement breakpoint start right click on the Control Flow and click on the EditBreakPoint on the option
After clicking on EditBreakpoint a window open from where you can chose the breakpoint option as per given above description and click on OK now breakpoint is applied on task flow.
Now you notice a red point on the Task where you applied the breakpoint this indicate there is a breakpoint on the task. Let's run the package now you see what happen when the breakpoint is reached, a title yellow arrow is added to the breakpoint arrow.
To get some information there are some number of things can be use once a breakpoint has been used.
Start with Call Stack Window which provide information where the breakpoint is located.
Next is Breakpoint window where all breakpoint is listed there, the blue area which show all listed Breakpoints from where you can disable and enable breakpoints .
Second red area is the control panel from here you can remove the breakpoint from the task.
Output window show the progress of the package and breakpoint.
Local Window the most important window the breakpoint bring which contains information on the current status of package execution and the amount of the time in which the package has been executing.
It contains all of the package variables which troubleshoot some odd package behavior it is related to variables not being populated as I thought they should. This is the best way to finding out what the package is doing during execution