Filter a filtered relation

[Charity]

So I have Invoices to invoice lineitems one to many.  And say there are 190,000 lineitems but only 20 belong to this invoice.  If I then use a portal of lineitems on invoices based upon match of invoiceID which I then filter on the portal so only certain records come up such as only shipping = UPS, is it filtering on the 20 lineitems or all 190,000.  I have read many things but I am still confused. sorry

it is impossible to see how it is being filtered so I can't find my answer. added --- i mean is the portal filtering 190,000 records or 20?

Edited February 28, 2017 by Charity

[webko]

20

The relationship sets the initial number of records being dealt with

[Charity]

Thank you Webko.  So what I have been reading about filtered portals, that filter portals look at all records which is why they can be slow, is not exactly right?  then it means filtered looks at all records from the relation and then only needs to filter further from there?  sorry I swear there are over 30 posts here and fmi which contradict themselves about it so I want to be sure I understand.

so the relation limits first so the burden is less on the filtered portal which only takes it from there?  sorry to ask again i just want to be sure I understand.  Has that changed? may be it used to apply filtered portal first and that changed?

[comment]

2 hours ago, Charity said:

 So what I have been reading about filtered portals, that filter portals look at all records which is why they can be slow, is not exactly right?

The filter looks at all related records. It does not evaluate other records.