Github user apivovarov commented on a diff in the pull request:
https://github.com/apache/flink/pull/2485#discussion_r78270796
--- Diff: docs/dev/table_api.md ---
@@ -2457,3 +2457,27 @@ The Table API provides a configuration (the
so-called `TableConfig`) to modify r
By default, the Table API supports `null` values. Null handling can be
disabled to improve preformance by setting the `nullCheck` property in the
`TableConfig` to `false`.
{% top %}
+
+Explaining a Table
+----
+The Table API provides a mechanism to describe the graph of operations
that leads to the resulting output. This is done through the
`TableEnvironment#explain(table)` method. It returns a string describing two
graphs: the Abstract Syntax Tree of the relational algebra query and the
Flink's Execution Plan of the equivalent Flink's Job.
+
+Table `explain` is supported for both `BatchTableEnvironment` and
`StreamTableEnvironment`. Currently `StreamTableEnvironment` doesn't support
the explanation of the Execution Plan.
+
+
+<div data-lang="scala" markdown="1">
+{% highlight scala %}
+ val env = StreamExecutionEnvironment.getExecutionEnvironment
+ val tEnv = TableEnvironment.getTableEnvironment(env)
+
+ val table1 = env.fromElements((1, "hello")).toTable(tEnv, 'count, 'word)
+ val table2 = env.fromElements((1, "hello")).toTable(tEnv, 'count, 'word)
+ val table = table1.unionAll(table2)
+
+ val explanation:String = tEnv.explain(table)
--- End diff --
put space before String
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