SERVER-15527 change rejectedPlansExecution to allPlansExecution

5 files changed, 63 insertions, 105 deletions

diff --git a/jstests/core/explain_shell_helpers.js b/jstests/core/explain_shell_helpers.js
index 5cc0a4bbfd3..785dc926b99 100644
--- a/jstests/core/explain_shell_helpers.js
+++ b/jstests/core/explain_shell_helpers.js
@@ -35,14 +35,14 @@ explain = t.explain(true).find().finish();
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert("rejectedPlansExecution" in explain.executionStats);
+assert("allPlansExecution" in explain.executionStats);
 
 // .explain(true) after .find().
 explain = t.find().explain(true);
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert("rejectedPlansExecution" in explain.executionStats);
+assert("allPlansExecution" in explain.executionStats);
 
 //
 // Test verbosity specifiers.
@@ -63,24 +63,24 @@ explain = t.explain("executionStats").find().finish();
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert(!("rejectedPlansExecution" in explain.executionStats));
+assert(!("allPlansExecution" in explain.executionStats));
 explain = t.find().explain("executionStats");
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert(!("rejectedPlansExecution" in explain.executionStats));
+assert(!("allPlansExecution" in explain.executionStats));
 
 // "allPlansExecution"
 explain = t.explain("allPlansExecution").find().finish();
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert("rejectedPlansExecution" in explain.executionStats);
+assert("allPlansExecution" in explain.executionStats);
 explain = t.find().explain("allPlansExecution");
 assert.commandWorked(explain);
 assert("queryPlanner" in explain);
 assert("executionStats" in explain);
-assert("rejectedPlansExecution" in explain.executionStats);
+assert("allPlansExecution" in explain.executionStats);
 
 //
 // Tests for DBExplainQuery helpers.
diff --git a/src/mongo/db/exec/multi_plan.cpp b/src/mongo/db/exec/multi_plan.cpp
index 2732c501bba..3db8e3e4dd7 100644
--- a/src/mongo/db/exec/multi_plan.cpp
+++ b/src/mongo/db/exec/multi_plan.cpp
@@ -30,14 +30,15 @@
 
 #include "mongo/platform/basic.h"
 
+#include <algorithm>
+#include <math.h>
+
+#include "mongo/base/owned_pointer_vector.h"
 #include "mongo/db/exec/multi_plan.h"
 #include "mongo/db/exec/scoped_timer.h"
 #include "mongo/db/exec/working_set_common.h"
 #include "mongo/util/mongoutils/str.h"
 
-#include <algorithm>
-#include <math.h>
-
 // for updateCache
 #include "mongo/db/catalog/collection.h"
 #include "mongo/db/catalog/database.h"
@@ -71,12 +72,6 @@ namespace mongo {
             delete _candidates[ix].solution;
             delete _candidates[ix].root;
         }
-
-        for (vector<PlanStageStats*>::iterator it = _candidateStats.begin();
-             it != _candidateStats.end();
-             ++it) {
-            delete *it;
-        }
     }
 
     void MultiPlanStage::addPlan(QuerySolution* solution, PlanStage* root,
@@ -298,20 +293,19 @@ namespace mongo {
     }
 
     vector<PlanStageStats*> MultiPlanStage::generateCandidateStats() {
+        OwnedPointerVector<PlanStageStats> candidateStats;
+
         for (size_t ix = 0; ix < _candidates.size(); ix++) {
             if (ix == (size_t)_bestPlanIdx) { continue; }
             if (ix == (size_t)_backupPlanIdx) { continue; }
 
-            // Remember the stats for the candidate plan because we always show it on an
-            // explain. (The {verbose:false} in explain() is client-side trick; we always
-            // generate a "verbose" explain.)
             PlanStageStats* stats = _candidates[ix].root->getStats();
             if (stats) {
-                _candidateStats.push_back(stats);
+                candidateStats.push_back(stats);
             }
         }
 
-        return _candidateStats;
+        return candidateStats.release();
     }
 
     bool MultiPlanStage::workAllPlans(size_t numResults) {
@@ -362,38 +356,6 @@ namespace mongo {
         return !doneWorking;
     }
 
-    Status MultiPlanStage::executeAllPlans() {
-        // Boolean vector keeping track of which plans are done.
-        vector<bool> planDone(_candidates.size(), false);
-
-        // Number of plans that are done.
-        size_t doneCount = 0;
-
-        while (doneCount < _candidates.size()) {
-            for (size_t i = 0; i < _candidates.size(); i++) {
-                if (planDone[i]) {
-                    continue;
-                }
-
-                WorkingSetID id = WorkingSet::INVALID_ID;
-                PlanStage::StageState state = _candidates[i].root->work(&id);
-
-                if (PlanStage::IS_EOF == state || PlanStage::DEAD == state) {
-                    doneCount++;
-                    planDone[i] = true;
-                }
-                else if (PlanStage::FAILURE == state) {
-                    // Propogate error.
-                    BSONObj errObj;
-                    WorkingSetCommon::getStatusMemberObject(*_candidates[i].ws, id, &errObj);
-                    return Status(ErrorCodes::BadValue, WorkingSetCommon::toStatusString(errObj));
-                }
-            }
-        }
-
-        return Status::OK();
-    }
-
     void MultiPlanStage::saveState() {
         for (size_t i = 0; i < _candidates.size(); ++i) {
             _candidates[i].root->saveState();
diff --git a/src/mongo/db/exec/multi_plan.h b/src/mongo/db/exec/multi_plan.h
index 689665e81f6..964d71443d0 100644
--- a/src/mongo/db/exec/multi_plan.h
+++ b/src/mongo/db/exec/multi_plan.h
@@ -111,19 +111,11 @@ namespace mongo {
         //
 
         /**
-         * Gathers execution stats for all losing plans.
+         * Gathers execution stats for all losing plans. Caller takes ownership of
+         * all pointers in the returned vector.
          */
         vector<PlanStageStats*> generateCandidateStats();
 
-        /**
-         * Runs the candidate plans until each has either hit EOF or returned DEAD. Results
-         * from the plans are thrown out, but execution stats are gathered.
-         *
-         * You should call this after calling pickBestPlan(...). It expects that a winning plan
-         * has already been selected.
-         */
-        Status executeAllPlans();
-
         static const char* kStageType;
 
     private:
@@ -156,9 +148,6 @@ namespace mongo {
         // tranferred to the PlanExecutor that wraps this stage.
         std::vector<CandidatePlan> _candidates;
 
-        // Candidate plans' stats. Owned here.
-        std::vector<PlanStageStats*> _candidateStats;
-
         // index into _candidates, of the winner of the plan competition
         // uses -1 / kNoSuchPlan when best plan is not (yet) known
         int _bestPlanIdx;
diff --git a/src/mongo/db/query/explain.cpp b/src/mongo/db/query/explain.cpp
index 234f86b5f30..83574eae575 100644
--- a/src/mongo/db/query/explain.cpp
+++ b/src/mongo/db/query/explain.cpp
@@ -30,6 +30,7 @@
 
 #include "mongo/db/query/explain.h"
 
+#include "mongo/base/owned_pointer_vector.h"
 #include "mongo/db/exec/multi_plan.h"
 #include "mongo/db/query/get_executor.h"
 #include "mongo/db/query/plan_executor.h"
@@ -561,20 +562,17 @@ namespace mongo {
         // Inspect the tree to see if there is a MultiPlanStage.
         MultiPlanStage* mps = getMultiPlanStage(exec->getRootStage());
 
-        // The executionStats verbosity level requires that we run the winning plan
-        // until it finishes.
-        if (verbosity >= ExplainCommon::EXEC_STATS) {
-            Status s = exec->executePlan();
-            if (!s.isOK()) {
-                return s;
-            }
+        // Get stats of the winning plan from the trial period, if the verbosity level
+        // is high enough and there was a runoff between multiple plans.
+        auto_ptr<PlanStageStats> winningStatsTrial;
+        if (verbosity >= ExplainCommon::EXEC_ALL_PLANS && NULL != mps) {
+            winningStatsTrial.reset(exec->getStats());
+            invariant(winningStatsTrial.get());
         }
 
-        // The allPlansExecution verbosity level requires that we run all plans to completion,
-        // if there are multiple candidates. If 'mps' is NULL, then there was only one candidate,
-        // and we don't have to worry about gathering stats for rejected plans.
-        if (verbosity == ExplainCommon::EXEC_ALL_PLANS && NULL != mps) {
-            Status s = mps->executeAllPlans();
+        // If we need execution stats, then run the plan in order to gather the stats.
+        if (verbosity >= ExplainCommon::EXEC_STATS) {
+            Status s = exec->executePlan();
             if (!s.isOK()) {
                 return s;
             }
@@ -587,10 +585,10 @@ namespace mongo {
         // Get stats for the winning plan.
         scoped_ptr<PlanStageStats> winningStats(exec->getStats());
 
-        // Get stats for the rejected plans, if there were rehected plans.
-        vector<PlanStageStats*> rejectedStats;
+        // Get stats for the rejected plans, if more than one plan was considered.
+        OwnedPointerVector<PlanStageStats> allPlansStats;
         if (NULL != mps) {
-            rejectedStats = mps->generateCandidateStats();
+            allPlansStats = mps->generateCandidateStats();
         }
 
         //
@@ -599,7 +597,7 @@ namespace mongo {
 
         CanonicalQuery* query = exec->getCanonicalQuery();
         if (verbosity >= ExplainCommon::QUERY_PLANNER) {
-            generatePlannerInfo(query, winningStats.get(), rejectedStats, out);
+            generatePlannerInfo(query, winningStats.get(), allPlansStats.vector(), out);
         }
 
         if (verbosity >= ExplainCommon::EXEC_STATS) {
@@ -609,16 +607,25 @@ namespace mongo {
             long long totalTimeMillis = opCtx->getCurOp()->elapsedMillis();
             generateExecStats(winningStats.get(), verbosity, &execBob, totalTimeMillis);
 
-            // Also generate exec stats for each rejected plan, if the verbosity level
-            // is high enough.
+            // Also generate exec stats for all plans, if the verbosity level is high enough.
+            // These stats reflect what happened during the trial period that ranked the plans.
             if (verbosity >= ExplainCommon::EXEC_ALL_PLANS) {
-                BSONArrayBuilder rejectedBob(execBob.subarrayStart("rejectedPlansExecution"));
-                for (size_t i = 0; i < rejectedStats.size(); ++i) {
-                    BSONObjBuilder planBob(rejectedBob.subobjStart());
-                    generateExecStats(rejectedStats[i], verbosity, &planBob);
+                // If we ranked multiple plans against each other, then add stats collected
+                // from the trial period of the winning plan. The "allPlansExecution" section
+                // will contain an apples-to-apples comparison of the winning plan's stats against
+                // all rejected plans' stats collected during the trial period.
+                if (NULL != mps) {
+                    invariant(winningStatsTrial.get());
+                    allPlansStats.push_back(winningStatsTrial.release());
+                }
+
+                BSONArrayBuilder allPlansBob(execBob.subarrayStart("allPlansExecution"));
+                for (size_t i = 0; i < allPlansStats.size(); ++i) {
+                    BSONObjBuilder planBob(allPlansBob.subobjStart());
+                    generateExecStats(allPlansStats[i], verbosity, &planBob);
                     planBob.doneFast();
                 }
-                rejectedBob.doneFast();
+                allPlansBob.doneFast();
             }
 
             execBob.doneFast();
diff --git a/src/mongo/s/cluster_explain.cpp b/src/mongo/s/cluster_explain.cpp
index 6e0a928f85d..a90d4baa9a2 100644
--- a/src/mongo/s/cluster_explain.cpp
+++ b/src/mongo/s/cluster_explain.cpp
@@ -122,10 +122,10 @@ namespace mongo {
            return Status(ErrorCodes::InternalError, "no shards found for explain");
         }
 
-        // Count up the number of shards that have execution stats and rejected plans
+        // Count up the number of shards that have execution stats and all plans
         // execution level information.
         size_t numShardsExecStats = 0;
-        size_t numShardsRejectedExecStats = 0;
+        size_t numShardsAllPlansStats = 0;
 
         // Check that the result from each shard has a true value for "ok" and has
         // the expected "queryPlanner" field.
@@ -140,8 +140,8 @@ namespace mongo {
             if (shardResults[i].result.hasField("executionStats")) {
                 numShardsExecStats++;
                 BSONObj execStats = shardResults[i].result["executionStats"].Obj();
-                if (execStats.hasField("rejectedPlansExecution")) {
-                    numShardsRejectedExecStats++;
+                if (execStats.hasField("allPlansExecution")) {
+                    numShardsAllPlansStats++;
                 }
             }
         }
@@ -154,10 +154,10 @@ namespace mongo {
                                         << " had executionStats explain information.");
         }
 
-        // Either all shards should have rejected plans execution stats, or none should.
-        if (0 != numShardsRejectedExecStats && shardResults.size() != numShardsRejectedExecStats) {
+        // Either all shards should have all plans execution stats, or none should.
+        if (0 != numShardsAllPlansStats && shardResults.size() != numShardsAllPlansStats) {
             return Status(ErrorCodes::InternalError,
-                          str::stream() << "Only " << numShardsRejectedExecStats
+                          str::stream() << "Only " << numShardsAllPlansStats
                                         << "/" << shardResults.size()
                                         << " had allPlansExecution explain information.");
         }
@@ -278,32 +278,32 @@ namespace mongo {
 
         executionStagesBob.doneFast();
 
-        if (!shardResults[0].result["executionStats"].Obj().hasField("rejectedPlansExecution")) {
-            // The shards don't have execution stats for rejected plans, so we're done.
+        if (!shardResults[0].result["executionStats"].Obj().hasField("allPlansExecution")) {
+            // The shards don't have execution stats for all plans, so we're done.
             executionStatsBob.doneFast();
             return;
         }
 
-        // Add the rejected plans from each shard.
-        BSONArrayBuilder rejectedPlansExecBob(
-            executionStatsBob.subarrayStart("rejectedPlansExecution"));
+        // Add the allPlans stats from each shard.
+        BSONArrayBuilder allPlansExecBob(
+            executionStatsBob.subarrayStart("allPlansExecution"));
         for (size_t i = 0; i < shardResults.size(); i++) {
             BSONObjBuilder singleShardBob(execShardsBuilder.subobjStart());
 
             singleShardBob.append("shardName", shardResults[i].shardTarget.getName());
 
             BSONObj execStats = shardResults[i].result["executionStats"].Obj();
-            vector<BSONElement> rejectedPlans = execStats["rejectedPlansExecution"].Array();
+            vector<BSONElement> allPlans = execStats["allPlansExecution"].Array();
 
-            BSONArrayBuilder innerArrayBob(singleShardBob.subarrayStart("rejectedPlans"));
-            for (size_t j = 0; j < rejectedPlans.size(); j++) {
-                appendToArrayIfRoom(&innerArrayBob, rejectedPlans[j]);
+            BSONArrayBuilder innerArrayBob(singleShardBob.subarrayStart("allPlans"));
+            for (size_t j = 0; j < allPlans.size(); j++) {
+                appendToArrayIfRoom(&innerArrayBob, allPlans[j]);
             }
             innerArrayBob.done();
 
             singleShardBob.doneFast();
         }
-        rejectedPlansExecBob.doneFast();
+        allPlansExecBob.doneFast();
 
         executionStatsBob.doneFast();
     }