google cloud platform - BigQuery destination tables empty after Copy Datasets with Data Transfer

Question

On BigQuery I recently started noticing an issue with Data Transfers (https://console.cloud.google.com/bigquery/transfers).

When I click on a Dataset and then on Copy Dataset, I want to copy a dataset from the source to the destination. I input something like the following:

source
project name = pA
dataset name = dA
location = EU

destination
project name = pB
dataset name = dB
location = EU

Overwrite destination tables: Selected True (tables at destination were not empty so I want to overwrite it).

After I click on Copy I monitored the status within the Run History in which it gave the message "The transfer has run successfully". Clicking on it I also see that each individual table was completed successfully.

Now when I go to BigQuery and I query:

SELECT * FROM `pB.dB.some_table` LIMIT 1000

I receive:

This query returned no results.

What is happening? Why is it not working anymore? Why are my tables empty at destination?

Answer 1

Since you have confirmed that the source table is a streaming table, rows buffered by the streaming system are not immediately available for copy/export. They should become available within about 90 minutes of insertion.