[SPARK-13468][WEB UI] Fix a corner case where the Stage UI page should show DAG but it doesn't show

When uses clicks more than one time on any stage in the DAG graph on the *Job* web UI page, many new *Stage* web UI pages are opened, but only half of their DAG graphs are expanded.

After this PR's fix, every newly opened *Stage* page's DAG graph is expanded.

Before:
![](https://cloud.githubusercontent.com/assets/15843379/13279144/74808e86-db10-11e5-8514-cecf31af8908.png)

After:
![](https://cloud.githubusercontent.com/assets/15843379/13279145/77ca5dec-db10-11e5-9457-8e1985461328.png)

## What changes were proposed in this pull request?

- Removed the `expandDagViz` parameter for _Stage_ page and related codes
- Added a `onclick` function setting `expandDagVizArrowKey(false)` as `true`

## How was this patch tested?

Manual tests (with this fix) to verified this fix work:
- clicked many times on _Job_ Page's DAG Graph → each newly opened Stage page's DAG graph is expanded

Manual tests (with this fix) to verified this fix do not break features we already had:
- refreshed many times for a same _Stage_ page (whose DAG already expanded) → DAG remained expanded upon every refresh
- refreshed many times for a same _Stage_ page (whose DAG unexpanded) → DAG remained unexpanded upon every refresh
- refreshed many times for a same _Job_ page (whose DAG already expanded) → DAG remained expanded upon every refresh
- refreshed many times for a same _Job_ page (whose DAG unexpanded) → DAG remained unexpanded upon every refresh

Author: Liwei Lin <proflin.me@gmail.com>

Closes #11368 from proflin/SPARK-13468.

3 files changed, 2 insertions, 20 deletions

diff --git a/core/src/main/resources/org/apache/spark/ui/static/spark-dag-viz.js b/core/src/main/resources/org/apache/spark/ui/static/spark-dag-viz.js
index 4337c42087..1b0d4692d9 100644
--- a/core/src/main/resources/org/apache/spark/ui/static/spark-dag-viz.js
+++ b/core/src/main/resources/org/apache/spark/ui/static/spark-dag-viz.js
@@ -222,10 +222,11 @@ function renderDagVizForJob(svgContainer) {
       var attemptId = 0
       var stageLink = d3.select("#stage-" + stageId + "-" + attemptId)
         .select("a.name-link")
-        .attr("href") + "&expandDagViz=true";
+        .attr("href");
       container = svgContainer
         .append("a")
         .attr("xlink:href", stageLink)
+        .attr("onclick", "window.localStorage.setItem(expandDagVizArrowKey(false), true)")
         .append("g")
         .attr("id", containerId);
     }
diff --git a/core/src/main/scala/org/apache/spark/ui/UIUtils.scala b/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
index ddd7f713fe..0493513d66 100644
--- a/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
+++ b/core/src/main/scala/org/apache/spark/ui/UIUtils.scala
@@ -408,13 +408,6 @@ private[spark] object UIUtils extends Logging {
     </sup>
   }
 
-  /** Return a script element that automatically expands the DAG visualization on page load. */
-  def expandDagVizOnLoad(forJob: Boolean): Seq[Node] = {
-    <script type="text/javascript">
-      {Unparsed("$(document).ready(function() { toggleDagViz(" + forJob + ") });")}
-    </script>
-  }
-
   /**
    * Returns HTML rendering of a job or stage description. It will try to parse the string as HTML
    * and make sure that it only contains anchors with root-relative links. Otherwise,
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
index 0b68b88566..689ab7dd5e 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
@@ -107,10 +107,6 @@ private[ui] class StagePage(parent: StagesTab) extends WebUIPage("stage") {
       val taskPageSize = Option(parameterTaskPageSize).map(_.toInt).getOrElse(100)
       val taskPrevPageSize = Option(parameterTaskPrevPageSize).map(_.toInt).getOrElse(taskPageSize)
 
-      // If this is set, expand the dag visualization by default
-      val expandDagVizParam = request.getParameter("expandDagViz")
-      val expandDagViz = expandDagVizParam != null && expandDagVizParam.toBoolean
-
       val stageId = parameterId.toInt
       val stageAttemptId = parameterAttempt.toInt
       val stageDataOption = progressListener.stageIdToData.get((stageId, stageAttemptId))
@@ -263,13 +259,6 @@ private[ui] class StagePage(parent: StagesTab) extends WebUIPage("stage") {
       val dagViz = UIUtils.showDagVizForStage(
         stageId, operationGraphListener.getOperationGraphForStage(stageId))
 
-      val maybeExpandDagViz: Seq[Node] =
-        if (expandDagViz) {
-          UIUtils.expandDagVizOnLoad(forJob = false)
-        } else {
-          Seq.empty
-        }
-
       val accumulableHeaders: Seq[String] = Seq("Accumulable", "Value")
       def accumulableRow(acc: AccumulableInfo): Seq[Node] = {
         (acc.name, acc.value) match {
@@ -578,7 +567,6 @@ private[ui] class StagePage(parent: StagesTab) extends WebUIPage("stage") {
       val content =
         summary ++
         dagViz ++
-        maybeExpandDagViz ++
         showAdditionalMetrics ++
         makeTimeline(
           // Only show the tasks in the table