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 Determining Actual Upload Start Time vs Queue Time in Aspera CSV Exports

Chuck Kahn's profile image
Chuck Kahn posted Tue February 03, 2026 07:47 PM

Hello,

I’m reviewing Aspera package metadata exported to CSV and trying to calculate effective upload speeds for sequentially released packages (e.g., break and wrap dailies).

In cases where multiple packages are released minutes or seconds apart, the CSV provides timestamps such as editReleaseDate, but it’s unclear whether this reflects:

  • actual transfer commencement (first byte sent), or

  • enqueue / release time while the package waits behind earlier transfers.

When packages are serialized on a constrained uplink, using editReleaseDate for later packages appears to distort speed calculations by including queue time.

My question:
Is there any field available—either in the CSV export, logs, or API—that indicates the actual start of data transfer for a given package (i.e., when the upload truly begins rather than when it is released or queued)?

If not, is the recommended interpretation that only the first package in a serialized sequence can be used to infer real uplink throughput?

Thank you for any clarification.

BEN FORSYTH's profile image
BEN FORSYTH posted Wed February 04, 2026 08:25 PM

Hi Chuck,

The transfers have an effective_rate that is logged for each transfer. The calculation is the total data / total transfer time. You will see in the ascp logs in the lines that contain FASP Session Statistics

This value is available from various API endpoints across the platform.

If you are using Aspera Faspex, here is how you would retrieve that information from Faspex APIs.

https://developer.ibm.com/apis/catalog/aspera--ibm-aspera-faspex-5-0-api/api/API--aspera--ibm-aspera-faspex-api#getPackageUploadDetails
Sample response after transfer is in progress
 
{"upload_status":"transferring","start_time":"2026-02-04T20:49:55.000Z","completion_time":null,"percentage_complete":"2.5418701171875","time_remaining":"00:01:20","bytes_written":"2665344","bytes_total":"104857600","time_elapsed":"2.09336","average_rate":"10185898.268811861”}
Another sample response after transfer is complete
{"upload_status":"completed","start_time":"2026-02-04T20:49:55.000Z","completion_time":"2026-02-04T20:50:45.000Z","percentage_complete":"100.0","time_remaining":"00:00:00","bytes_written":"104857600","bytes_total":"104857600","time_elapsed":"50.6204","average_rate":"16571595.641282963"}
thanks,
Ben

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