I am glad to share a couple of nodes I have made to allow uploading very large datasets (gigabytes of e.g. CSV) to a back-end (e.g. SQL database) through Node-RED, with a UI for Node-RED Dashboard.
The first node is a widget UI for Node-RED dashboard, which streams the data to Node-RED as chunks (text or binary) with proper back-pressure (i.e. waiting for the back-end to be ready before sending more data, to avoid memory exhaustion) https://github.com/alexandrainst/node-red-contrib-ui-upload
The second node is a normal Node-RED node, which is similar to the default "split" node, but more powerful: it supports a stream of binary or text chunks as input, supports back-pressure (wait for the rest of the downstream flow to be ready before informing the upstream flow to send more data), and outputs lines of text, either one by one, or by batches of lines for higher performance (e.g. when inserting in an SQL database). https://github.com/alexandrainst/node-red-contrib-chunks-to-lines
I hope some of you will find that useful. Feedback welcome!