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.