pitrou commented on a change in pull request #12624: URL: https://github.com/apache/arrow/pull/12624#discussion_r826117777
########## File path: docs/source/cpp/env_vars.rst ########## @@ -0,0 +1,128 @@ +.. Licensed to the Apache Software Foundation (ASF) under one +.. or more contributor license agreements. See the NOTICE file +.. distributed with this work for additional information +.. regarding copyright ownership. The ASF licenses this file +.. to you under the Apache License, Version 2.0 (the +.. "License"); you may not use this file except in compliance +.. with the License. You may obtain a copy of the License at + +.. http://www.apache.org/licenses/LICENSE-2.0 + +.. Unless required by applicable law or agreed to in writing, +.. software distributed under the License is distributed on an +.. "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +.. KIND, either express or implied. See the License for the +.. specific language governing permissions and limitations +.. under the License. + +===================== +Environment Variables +===================== + +The following environment variables can be used to affect the behavior of +Arrow C++ at runtime. Many of these variables are inspected only once per +process (for example, when the Arrow C++ DLL is loaded), so you cannot assume +that changing their value later will have an effect. + +.. envvar:: ARROW_DEBUG_MEMORY_POOL + + Enable rudimentary memory checks to guard against buffer overflows. + The value of this environment variable selects the behavior when a + buffer overflow is detected: + + - ``abort`` exits the processus with a non-zero return value; + - ``trap`` issues a platform-specific debugger breakpoint / trap instruction; + - ``warn`` prints a warning on stderr and continues execution; + - an empty value disables memory checks. + + .. note:: + While this functionality can be useful and has little overhead, it + is not a replacement for more sophisticated memory checking utilities + such as `Valgrind <https://valgrind.org/>`_ or + `Address Sanitizer <https://clang.llvm.org/docs/AddressSanitizer.html>`_. + +.. envvar:: ARROW_DEFAULT_MEMORY_POOL + + The backend to be used for the default :ref:`memory pool <cpp_memory_pool>`. + Possible values are among ``jemalloc``, ``mimalloc`` and ``system``, + depending on which backends were enabled when + :ref:`building Arrow C++ <building-arrow-cpp>`. + +.. envvar:: ARROW_LIBHDFS_DIR + + The directory containing the C HDFS library (``hdfs.dll`` on Windows, + ``libhdfs.dylib`` on macOS, ``libhdfs.so`` on other platforms). + Alternatively, one can set :envvar:`HADOOP_HOME`. + +.. envvar:: ARROW_TRACING_BACKEND + + The backend where to export `OpenTelemetry <https://opentelemetry.io/>`_-based + execution traces. Possible values are: + + - ``ostream``: emit textual log messages to stdout; Review comment: @lidavidm It seems once cannot choose between stdout/stderr? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
