CHOOSING THE RIGHT REPORT
Because of the extensive reporting options available in the Google Ads API, determining the correct report for a particular business need can be tricky.
Use the chart below to determine the most suitable report, then check out the details for that report on the Report Types page.
Source & Copyright: https://developers.google.com/adwords/api/docs/guides/reporting
The report download request may time out on extremely large data sets. There is no explicit data size limit; however, due to a variety of factors, the server may return an error if the report is too large.
If you encounter timeouts or errors, try a shorter date range or use predicates to break up the report request into multiple, smaller requests. For example, instead of running a single report for all campaigns, you could submit multiple requests that each filter for a subset of Campaign IDs.