Google DataFlow Cannot read and write in different

问题:

I'm writing a very basic DataFlow pipeline using the Python SDK v0.5.5. The pipeline uses a BigQuerySource with a query passed in, which is querying BigQuery tables from datasets that reside in EU.

When executing the pipeline I'm getting the following error (project name anonymized):

HttpError: HttpError accessing <https://www.googleapis.com/bigquery/v2/projects/XXXXX/queries/93bbbecbc470470cb1bbb9c22bd83e9d?alt=json&maxResults=10000>: response: <{'status': '400', 'content-length': '292', 'x-xss-protection': '1; mode=block', 'x-content-type-options': 'nosniff', 'transfer-encoding': 'chunked', 'expires': 'Thu, 09 Feb 2017 10:28:04 GMT', 'vary': 'Origin, X-Origin', 'server': 'GSE', '-content-encoding': 'gzip', 'cache-control': 'private, max-age=0', 'date': 'Thu, 09 Feb 2017 10:28:04 GMT', 'x-frame-options': 'SAMEORIGIN', 'alt-svc': 'quic=":443"; ma=2592000; v="35,34"', 'content-type': 'application/json; charset=UTF-8'}>, content <{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "invalid",
    "message": "Cannot read and write in different locations: source: EU, destination: US"
   }
  ],
  "code": 400,
  "message": "Cannot read and write in different locations: source: EU, destination: US"
 }
}

The error also occurs when specifying a project, dataset and table name. However there's no error when selecting data from the public datasets available (which reside in US - like shakespeare). I also have jobs running v0.4.4 of the SDK which don't have this error.

The difference between these versions is the creation of a temp dataset, as is shown by the warning at pipeline startup:

WARNING:root:Dataset does not exist so we will create it

I've briefly taken a look at the different versions of the SDK and the difference seems to be around this temp dataset. It looks like the current version creates a temp dataset by default with a location in US (taken from master):

• Creation of dataset
• Default dataset location

I haven't found a way to disable the creation of these temp datasets. Am I overlooking something, or is this indeed not working anymore when selecting data from EU datasets?

回答1:

Thanks for reporting this issue. I assume you are using DirectRunner. We changed the implementation of BigQuery read transform for DirectRunner to create a temporary dataset (for SDK versions 0.5.1 and later) to support large datasets. Seems like we are not setting the region correctly here. We'll look into fixing this.

This issue should not occur if you use DataflowRunner which creates temporary datasets in the correct region.