A number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.
Endpoint Overrides
GOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT=...overrides theEndpointOption(which defaults to "datafusion.googleapis.com") used byMakeDataFusionConnection().
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also setGOOGLE_CLOUD_CPP_ENABLE_CLOGto produce any output on the program's console.
See Also
google::cloud::LoggingComponentsOptionGOOGLE_CLOUD_CPP_TRACING_OPTIONS=...: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.
See Also
google::cloud::GrpcTracingOptionsOptionGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes: turns on logging in the library, basically the library always "logs" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis document provides a comprehensive list of DataFusion library versions, starting from the latest release candidate, 2.37.0-rc, and going down to version 2.13.0, each linked to its respective documentation.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables like \u003ccode\u003eGOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT\u003c/code\u003e, \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e can be utilized to configure and troubleshoot the DataFusion library's behavior, such as overriding the default endpoint and enabling tracing or logging.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e environment variable is used in examples and tests to set the GCP project, however it has no impact on the library's functionality.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e allows for customization of gRPC tracing behavior, such as formatting and truncation of output.\u003c/p\u003e\n"],["\u003cp\u003eTracing can be enabled for most gRPC calls by using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, while enabling logging in the library can be done with \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,["Version latestkeyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/datafusion/latest/datafusion-env)\n- [2.41.0](/cpp/docs/reference/datafusion/2.41.0/datafusion-env)\n- [2.40.0](/cpp/docs/reference/datafusion/2.40.0/datafusion-env)\n- [2.39.0](/cpp/docs/reference/datafusion/2.39.0/datafusion-env)\n- [2.38.0](/cpp/docs/reference/datafusion/2.38.0/datafusion-env)\n- [2.37.0](/cpp/docs/reference/datafusion/2.37.0/datafusion-env)\n- [2.36.0](/cpp/docs/reference/datafusion/2.36.0/datafusion-env)\n- [2.35.0](/cpp/docs/reference/datafusion/2.35.0/datafusion-env)\n- [2.34.0](/cpp/docs/reference/datafusion/2.34.0/datafusion-env)\n- [2.33.0](/cpp/docs/reference/datafusion/2.33.0/datafusion-env)\n- [2.32.0](/cpp/docs/reference/datafusion/2.32.0/datafusion-env)\n- [2.31.0](/cpp/docs/reference/datafusion/2.31.0/datafusion-env)\n- [2.30.0](/cpp/docs/reference/datafusion/2.30.0/datafusion-env)\n- [2.29.0](/cpp/docs/reference/datafusion/2.29.0/datafusion-env)\n- [2.28.0](/cpp/docs/reference/datafusion/2.28.0/datafusion-env)\n- [2.27.0](/cpp/docs/reference/datafusion/2.27.0/datafusion-env)\n- [2.26.0](/cpp/docs/reference/datafusion/2.26.0/datafusion-env)\n- [2.25.1](/cpp/docs/reference/datafusion/2.25.1/datafusion-env)\n- [2.24.0](/cpp/docs/reference/datafusion/2.24.0/datafusion-env)\n- [2.23.0](/cpp/docs/reference/datafusion/2.23.0/datafusion-env)\n- [2.22.1](/cpp/docs/reference/datafusion/2.22.1/datafusion-env)\n- [2.21.0](/cpp/docs/reference/datafusion/2.21.0/datafusion-env)\n- [2.20.0](/cpp/docs/reference/datafusion/2.20.0/datafusion-env)\n- [2.19.0](/cpp/docs/reference/datafusion/2.19.0/datafusion-env)\n- [2.18.0](/cpp/docs/reference/datafusion/2.18.0/datafusion-env)\n- [2.17.0](/cpp/docs/reference/datafusion/2.17.0/datafusion-env)\n- [2.16.0](/cpp/docs/reference/datafusion/2.16.0/datafusion-env)\n- [2.15.1](/cpp/docs/reference/datafusion/2.15.1/datafusion-env)\n- [2.14.0](/cpp/docs/reference/datafusion/2.14.0/datafusion-env)\n- [2.13.0](/cpp/docs/reference/datafusion/2.13.0/datafusion-env) \n\nEnvironment Variables\n=====================\n\nA number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.\n\nEndpoint Overrides\n------------------\n\n- `GOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"datafusion.googleapis.com\") used by `MakeDataFusionConnection()`.\n\n###### See Also\n\n[`google::cloud::EndpointOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1EndpointOption.html)\n\nLogging\n-------\n\n`GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc`: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also set `GOOGLE_CLOUD_CPP_ENABLE_CLOG` to produce any output on the program's console.\n\n###### See Also\n\n[`google::cloud::LoggingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1LoggingComponentsOption.html)`GOOGLE_CLOUD_CPP_TRACING_OPTIONS=...`: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.\n\n###### See Also\n\n[`google::cloud::GrpcTracingOptionsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcTracingOptionsOption.html)`GOOGLE_CLOUD_CPP_ENABLE_CLOG=yes`: turns on logging in the library, basically the library always \"logs\" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.\n\n###### See Also\n\n[`google::cloud::LogBackend`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogBackend.html)\n\n###### See Also\n\n[`google::cloud::LogSink`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogSink.html)\n\nSetting the Default Project\n---------------------------\n\n`GOOGLE_CLOUD_PROJECT=...`: is used in examples and integration tests to configure the GCP project. This has no effect in the library."]]
