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

Five Stars

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

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 


Accepted Solutions
Twelve Stars

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

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

Francois Denis

Tag as "solved" for others! Kudos to thanks!


All Replies
Twelve Stars

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

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

Regards

Francois Denis

Tag as "solved" for others! Kudos to thanks!

Five Stars

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

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?

Twelve Stars

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

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

Francois Denis

Tag as "solved" for others! Kudos to thanks!

Calling Talend Open Studio Users

The first 100 community members completing the Open Studio survey win a $10 gift voucher.

Start the survey

2019 GARNER MAGIC QUADRANT FOR DATA INTEGRATION TOOL

Talend named a Leader.

Get your copy

OPEN STUDIO FOR DATA INTEGRATION

Kickstart your first data integration and ETL projects.

Download now

What’s New for Talend Summer ’19

Watch the recorded webinar!

Watch Now

Best Practices for Using Context Variables with Talend – Part 4

Pick up some tips and tricks with Context Variables

Blog

How Media Organizations Achieved Success with Data Integration

Learn how media organizations have achieved success with Data Integration

Read

6 Ways to Start Utilizing Machine Learning with Amazon We Services and Talend

Look at6 ways to start utilizing Machine Learning with Amazon We Services and Talend

Blog