diff --git a/docs/source/compatibility.md b/docs/source/compatibility.md new file mode 100644 index 0000000000..6e69f84c51 --- /dev/null +++ b/docs/source/compatibility.md @@ -0,0 +1,40 @@ + + +# Compatibility Guide + +Comet aims to provide consistent results with the version of Apache Spark that is being used. + +This guide offers information about areas of functionality where there are known differences. + +## ANSI mode + +Comet currently ignores ANSI mode in most cases, and therefore can produce different results than Spark. By default, +Comet will fall back to Spark if ANSI mode is enabled. To enable Comet to accelerate queries when ANSI mode is enabled, +specify `spark.comet.ansi.enabled=true` in the Spark configuration. Comet's ANSI support is experimental and should not +be used in production. + +There is an [epic](https://github.com/apache/datafusion-comet/issues/313) where we are tracking the work to fully implement ANSI support. + +## Cast + +Comet currently delegates to Apache DataFusion for most cast operations, and this means that the behavior is not +guaranteed to be consistent with Spark. + +There is an [epic](https://github.com/apache/datafusion-comet/issues/286) where we are tracking the work to implement Spark-compatible cast expressions. diff --git a/docs/source/index.rst b/docs/source/index.rst index 2cff77fd9a..c8f2735b92 100644 --- a/docs/source/index.rst +++ b/docs/source/index.rst @@ -43,6 +43,7 @@ GitHub repository at https://github.com/apache/datafusion-comet. :maxdepth: 1 :caption: Project Links + compatibility Github and Issue Tracker .. _toc.asf-links: