SERVER-51724 Collect the number of cursor seeks per operation

3 files changed, 53 insertions, 0 deletions

diff --git a/src/mongo/db/stats/resource_consumption_metrics.cpp b/src/mongo/db/stats/resource_consumption_metrics.cpp
index 90d278ea072..072488d593d 100644
--- a/src/mongo/db/stats/resource_consumption_metrics.cpp
+++ b/src/mongo/db/stats/resource_consumption_metrics.cpp
@@ -58,6 +58,7 @@ static const char kDocUnitsWritten[] = "docUnitsWritten";
 static const char kIdxEntryBytesWritten[] = "idxEntryBytesWritten";
 static const char kIdxEntryUnitsWritten[] = "idxEntryUnitsWritten";
 static const char kDocUnitsReturned[] = "docUnitsReturned";
+static const char kCursorSeeks[] = "cursorSeeks";
 
 inline void appendNonZeroMetric(BSONObjBuilder* builder, const char* name, long long value) {
     if (value != 0) {
@@ -121,6 +122,7 @@ void ResourceConsumption::ReadMetrics::toBson(BSONObjBuilder* builder) const {
     builder->appendNumber(kIdxEntryUnitsRead, idxEntryUnitsRead);
     builder->appendNumber(kKeysSorted, keysSorted);
     builder->appendNumber(kDocUnitsReturned, docUnitsReturned);
+    builder->appendNumber(kCursorSeeks, cursorSeeks);
 }
 
 void ResourceConsumption::WriteMetrics::toBson(BSONObjBuilder* builder) const {
@@ -162,6 +164,7 @@ void ResourceConsumption::OperationMetrics::toBsonNonZeroFields(BSONObjBuilder*
     appendNonZeroMetric(builder, kIdxEntryUnitsRead, readMetrics.idxEntryUnitsRead);
     appendNonZeroMetric(builder, kKeysSorted, readMetrics.keysSorted);
     appendNonZeroMetric(builder, kDocUnitsReturned, readMetrics.docUnitsReturned);
+    appendNonZeroMetric(builder, kCursorSeeks, readMetrics.cursorSeeks);
 
     if (cpuTimer) {
         appendNonZeroMetric(builder, kCpuNanos, durationCount<Nanoseconds>(cpuTimer->getElapsed()));
@@ -247,6 +250,10 @@ bool ResourceConsumption::MetricsCollector::endScopedCollecting() {
     return wasCollecting;
 }
 
+void ResourceConsumption::MetricsCollector::incrementOneCursorSeek() {
+    _doIfCollecting([&] { _metrics.readMetrics.cursorSeeks++; });
+}
+
 ResourceConsumption::ScopedMetricsCollector::ScopedMetricsCollector(OperationContext* opCtx,
                                                                     const std::string& dbName,
                                                                     bool commandCollectsMetrics)
diff --git a/src/mongo/db/stats/resource_consumption_metrics.h b/src/mongo/db/stats/resource_consumption_metrics.h
index 5e49b6f5f9a..9ca51be3fa8 100644
--- a/src/mongo/db/stats/resource_consumption_metrics.h
+++ b/src/mongo/db/stats/resource_consumption_metrics.h
@@ -60,6 +60,7 @@ public:
             idxEntryUnitsRead += other.idxEntryUnitsRead;
             keysSorted += other.keysSorted;
             docUnitsReturned += other.docUnitsReturned;
+            cursorSeeks += other.cursorSeeks;
         }
 
         ReadMetrics& operator+=(const ReadMetrics& other) {
@@ -84,6 +85,8 @@ public:
         long long keysSorted = 0;
         // Number of document units returned by a query
         long long docUnitsReturned = 0;
+        // Number of cursor seeks
+        long long cursorSeeks = 0;
     };
 
     /* WriteMetrics maintains metrics for write operations. */
@@ -277,6 +280,14 @@ public:
          */
         void incrementOneIdxEntryWritten(size_t idxEntryBytesWritten);
 
+        /**
+         * This should be called once every time the storage engine successfully does a cursor seek.
+         * Note that if it takes multiple attempts to do a successful seek, this function should
+         * only be called once. If the seek does not find anything, this function should not be
+         * called.
+         */
+        void incrementOneCursorSeek();
+
     private:
         /**
          * Helper function that calls the Func when this collector is currently collecting metrics.
diff --git a/src/mongo/db/stats/resource_consumption_metrics_test.cpp b/src/mongo/db/stats/resource_consumption_metrics_test.cpp
index fea3bb0a456..b53e754b032 100644
--- a/src/mongo/db/stats/resource_consumption_metrics_test.cpp
+++ b/src/mongo/db/stats/resource_consumption_metrics_test.cpp
@@ -225,6 +225,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetrics) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 8);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 16);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 32);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     ASSERT(operationMetrics.hasCollectedMetrics());
@@ -236,6 +237,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetrics) {
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.idxEntryUnitsRead, 1);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.keysSorted, 16);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.docUnitsReturned, 32);
+    ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.cursorSeeks, 1);
 
     // Clear metrics so we do not double-count.
     operationMetrics.reset();
@@ -247,6 +249,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetrics) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 128);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 256);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 512);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     metricsCopy = globalResourceConsumption.getDbMetrics();
@@ -256,6 +259,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetrics) {
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.idxEntryUnitsRead, 1 + 8);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.keysSorted, 16 + 256);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.docUnitsReturned, 32 + 512);
+    ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.cursorSeeks, 1 + 1);
 }
 
 TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsSecondary) {
@@ -272,6 +276,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsSecondary) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 8);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 16);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 32);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     auto metricsCopy = globalResourceConsumption.getDbMetrics();
@@ -281,6 +286,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsSecondary) {
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryUnitsRead, 1);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.keysSorted, 16);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsReturned, 32);
+    ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.cursorSeeks, 1);
 
     // Clear metrics so we do not double-count.
     operationMetrics.reset();
@@ -292,6 +298,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsSecondary) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 128);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 256);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 512);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     metricsCopy = globalResourceConsumption.getDbMetrics();
@@ -301,6 +308,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsSecondary) {
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryUnitsRead, 1 + 8);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.keysSorted, 16 + 256);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsReturned, 32 + 512);
+    ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.cursorSeeks, 1 + 1);
 }
 
 TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
@@ -316,6 +324,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 8);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 16);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 32);
+        operationMetrics.incrementOneCursorSeek();
 
         ASSERT_OK(repl::ReplicationCoordinator::get(_opCtx.get())
                       ->setFollowerMode(repl::MemberState::RS_SECONDARY));
@@ -324,6 +333,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 128);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 256);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 512);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     auto metricsCopy = globalResourceConsumption.getAndClearDbMetrics();
@@ -333,12 +343,14 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.idxEntryUnitsRead, 0);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.keysSorted, 0);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.docUnitsReturned, 0);
+    ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.cursorSeeks, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docBytesRead, 2 + 32);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsRead, 2);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryBytesRead, 8 + 128);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryUnitsRead, 1 + 8);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.keysSorted, 16 + 256);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsReturned, 32 + 512);
+    ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.cursorSeeks, 1 + 1);
 
     operationMetrics.reset();
 
@@ -351,6 +363,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 8);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 16);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 32);
+        operationMetrics.incrementOneCursorSeek();
 
         ASSERT_OK(repl::ReplicationCoordinator::get(_opCtx.get())
                       ->setFollowerMode(repl::MemberState::RS_PRIMARY));
@@ -359,6 +372,7 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
         operationMetrics.incrementOneIdxEntryRead(_opCtx.get(), 128);
         operationMetrics.incrementKeysSorted(_opCtx.get(), 256);
         operationMetrics.incrementDocUnitsReturned(_opCtx.get(), 512);
+        operationMetrics.incrementOneCursorSeek();
     }
 
     metricsCopy = globalResourceConsumption.getAndClearDbMetrics();
@@ -368,12 +382,14 @@ TEST_F(ResourceConsumptionMetricsTest, IncrementReadMetricsAcrossStates) {
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.idxEntryUnitsRead, 1 + 8);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.keysSorted, 16 + 256);
     ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.docUnitsReturned, 32 + 512);
+    ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.cursorSeeks, 1 + 1);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docBytesRead, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsRead, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryBytesRead, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.idxEntryUnitsRead, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.keysSorted, 0);
     ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.docUnitsReturned, 0);
+    ASSERT_EQ(metricsCopy["db1"].secondaryReadMetrics.cursorSeeks, 0);
 }
 
 TEST_F(ResourceConsumptionMetricsTest, DocumentUnitsRead) {
@@ -596,4 +612,23 @@ TEST_F(ResourceConsumptionMetricsTest, CpuNanos) {
     globalCpuTime = globalResourceConsumption.getCpuTime();
     ASSERT_EQ(Nanoseconds(0), globalCpuTime);
 }
+
+TEST_F(ResourceConsumptionMetricsTest, CursorSeeks) {
+    auto& globalResourceConsumption = ResourceConsumption::get(getServiceContext());
+    auto& operationMetrics = ResourceConsumption::MetricsCollector::get(_opCtx.get());
+
+    int expectedSeeks = 0;
+
+    {
+        ResourceConsumption::ScopedMetricsCollector scope(_opCtx.get(), "db1");
+        operationMetrics.incrementOneCursorSeek();
+        operationMetrics.incrementOneCursorSeek();
+        operationMetrics.incrementOneCursorSeek();
+
+        expectedSeeks += 3;
+    }
+
+    auto metricsCopy = globalResourceConsumption.getDbMetrics();
+    ASSERT_EQ(metricsCopy["db1"].primaryReadMetrics.cursorSeeks, expectedSeeks);
+}
 }  // namespace mongo