What tools to use to visualize logical and physical query plans?

问题

I am familiar explain() (also WebUI). I was curious whether there are any tools that generate an image of the tree structure of the logical/physical plan before/after optimizations. That is the information returned by explain() as an image.

回答1:

A picture like a PNG or JPG? Never heard of one myself, but you can see the physical plan using web UI (that you've already mentioned).

The other phases of query execution are available using TreeNode methods which (among many methods that could help you out) give you my favorite numberedTreeString.

scala> println(q.queryExecution.analyzed.numberedTreeString)
00 Range (0, 5, step=1, splits=Some(8))

scala> println(q.queryExecution.executedPlan.numberedTreeString)
00 *Range (0, 5, step=1, splits=8)

You can save the output as JSON using toJSON or prettyJson to generate PNG (but I've never tried it out myself).

scala> println(q.queryExecution.executedPlan.prettyJson)
[ {
  "class" : "org.apache.spark.sql.execution.WholeStageCodegenExec",
  "num-children" : 1,
  "child" : 0
}, {
  "class" : "org.apache.spark.sql.execution.RangeExec",
  "num-children" : 0,
  "range" : [ {
    "class" : "org.apache.spark.sql.catalyst.plans.logical.Range",
    "num-children" : 0,
    "start" : 0,
    "end" : 5,
    "step" : 1,
    "numSlices" : 8,
    "output" : [ [ {
      "class" : "org.apache.spark.sql.catalyst.expressions.AttributeReference",
      "num-children" : 0,
      "name" : "id",
      "dataType" : "long",
      "nullable" : false,
      "metadata" : { },
      "exprId" : {
        "product-class" : "org.apache.spark.sql.catalyst.expressions.ExprId",
        "id" : 0,
        "jvmId" : "cb497d01-3b90-42a7-9ebf-ebe85578f763"
      },
      "isGenerated" : false
    } ] ]
  } ]
} ]

来源：https://stackoverflow.com/questions/44242201/what-tools-to-use-to-visualize-logical-and-physical-query-plans