text: // Test that even when the execution of a query fails, explain reports query
  // planner information.
  
  var t = db.explain_execution_error;
  t.drop();
  
  var result;
  
  /**
   * Asserts that explain reports an error in its execution stats section.
   */
  function assertExecError(explain) {
      var errorObj;
  
      var execStats = explain.executionStats;
      if (execStats.executionStages.stage == "SINGLE_SHARD") {
          errorObj = execStats.executionStages.shards[0];
      } else {
          errorObj = execStats;
      }
  
      assert.eq(false, errorObj.executionSuccess);
      assert("errorMessage" in errorObj);
      assert("errorCode" in errorObj);
  }
  
  /**
   * Asserts that explain reports success in its execution stats section.
   */
  function assertExecSuccess(explain) {
      var errorObj;
  
      var execStats = explain.executionStats;
      if (execStats.executionStages.stage == "SINGLE_SHARD") {
          errorObj = execStats.executionStages.shards[0];
      } else {
          errorObj = execStats;
      }
  
      assert.eq(true, errorObj.executionSuccess);
      assert(!("errorMessage" in errorObj));
      assert(!("errorCode" in errorObj));
  }
  
  // Make a string that exceeds 1 MB.
  var bigStr = "x";
  while (bigStr.length < (1024 * 1024)) {
      bigStr += bigStr;
  }
  
  // Make a collection that is about 40 MB.
  for (var i = 0; i < 40; i++) {
      assert.writeOK(t.insert({a: bigStr, b: 1, c: i}));
  }
  
  // A query which sorts the whole collection by "b" should throw an error due to hitting the
  // memory limit for sort.
  assert.throws(function() {
      t.find({a: {$exists: true}}).sort({b: 1}).itcount();
  });
  
  // Explain of this query should succeed at query planner verbosity.
  result = db.runCommand({
      explain: {find: t.getName(), filter: {a: {$exists: true}}, sort: {b: 1}},
      verbosity: "queryPlanner"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  
  // Explaining the same query at execution stats verbosity should succeed, but indicate that the
  // underlying operation failed.
  result = db.runCommand({
      explain: {find: t.getName(), filter: {a: {$exists: true}}, sort: {b: 1}},
      verbosity: "executionStats"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  assert("executionStats" in result);
  assertExecError(result);
  
  // The underlying operation should also report a failure at allPlansExecution verbosity.
  result = db.runCommand({
      explain: {find: t.getName(), filter: {a: {$exists: true}}, sort: {b: 1}},
      verbosity: "allPlansExecution"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  assert("executionStats" in result);
  assert("allPlansExecution" in result.executionStats);
  assertExecError(result);
  
  // Now we introduce two indices. One provides the requested sort order, and
  // the other does not.
  t.ensureIndex({b: 1});
  t.ensureIndex({c: 1});
  
  // The query should no longer fail with a memory limit error because the planner can obtain
  // the sort by scanning an index.
  assert.eq(40, t.find({c: {$lt: 40}}).sort({b: 1}).itcount());
  
  // The explain should succeed at all verbosity levels because the query itself succeeds.
  // First test "queryPlanner" verbosity.
  result = db.runCommand({
      explain: {find: t.getName(), filter: {c: {$lt: 40}}, sort: {b: 1}},
      verbosity: "queryPlanner"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  
  result = db.runCommand({
      explain: {find: t.getName(), filter: {c: {$lt: 40}}, sort: {b: 1}},
      verbosity: "executionStats"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  assert("executionStats" in result);
  assertExecSuccess(result);
  
  // We expect allPlansExecution verbosity to show execution stats for both candidate plans.
  result = db.runCommand({
      explain: {find: t.getName(), filter: {c: {$lt: 40}}, sort: {b: 1}},
      verbosity: "allPlansExecution"
  });
  assert.commandWorked(result);
  assert("queryPlanner" in result);
  assert("executionStats" in result);
  assert("allPlansExecution" in result.executionStats);
  assertExecSuccess(result);
  