Preview not available for Flow snaps
Certain flow snaps like “Filter”, “Head”, “Tail” when used in a complex pipeline doesn’t generate a preview while validating the entire pipeline however these generate a preview if the pipeline is simple.
For instance, if I’m trying to read data from an excel file with 100k+ records and use either ‘filter’ or ‘head/tail’, I can see the preview when the pipeline has been validated but it doesn’t generate one when the pipeline is huge. Any specific reason behind this?
I would want to see the preview as the pipeline that I’m currently developing is a complex one (multiple snaps prior to “flow” snaps), thereafter it needs a ‘filter + head/tail’ (i.e. flow snaps) and then it will again require a bunch of other snaps after those ‘filter + head/tail’ making it complex again.
Help on this matter would be highly appreciated.
Regards,
Darsh
What @dmiller probably meant, is, that the 50 records validating doesn’t meet the criteria in the filter.
Try increasing the preview count.
I’m pretty sure there’s nothing wrong with the Filter snap, and to prove that, you can try and add
trueas a filter expression and re-validate. You should see all 50 records passed through.There are a couple of things that needs to be taken into consideration here:
Firstly, Snap Execution should be set to "Validate & Execute", any other settings wouldn't generate a preview for you.
Secondly, change the Preview Document Count to Max i.e. 2000 as seen below:
Thirdly, if you're dealing with a huge dataset let's say 50k and you only have 100 records out of 50k that satisfies the condition in the filter snap, you may or may not see them in the preview as the order of records displayed in preview is not guaranteed, you can use a SORT snap before filter if you know the first 50 will suffice the condition; if that's the case then you will see the output preview for sure.
Thank you.
Best Regards,
Darsh
