exact use of tmap (reload at each row and load once) options

[Anonymous]

Hi Guys,

I have a question regarding tmap lookup models options available

Load once : It is used to load the lookup data once into the memory (regardless of main flow data                           volume)

Reload at each row : I have read in many blogs that it is used when the main flow has lesser data                                          compared to lookup flow and for each and every main row the lookup is                                                  reloaded every time

But in first option(load once) even though the main flow is huge we are not reloading the lookup for every main row but in second option why do we need to reload even though if the main flow is very small?

Is my question correct? or is there misunderstanding by me?

Could anyone please help me when can i use reload at each row option and exact use of that?

Please don't send me any other links to refer as i have gone through each and every of them

Hope I get a clear understanding in this talend forum

Thanks,

Kiran 

[fdenis]

reload each time is useful when you want to add dynamic filter on the lookup table. when filter information come from first data.

Regards

[Anonymous]

hi ,

thanks for the reply.

so you mean to say that its used to filter the lookup data based on main flow data right?

ex : main flow have emp_id in (1,2,3,4,5)

      so lookup query will be like

      select * from lookup where emp_id in ("+id_from_lookup+"); 

     for every empid from main flow the lookup will load only those specific records right?
     is this correct?

[fdenis · Accepted solution]

it's right. For each row allow you to define globalMap variable who can be used into lookup query.