SERVER-35602 Add support to benchRun for atClusterTime reads with adjustable getMore delays

1 files changed, 26 insertions, 3 deletions

diff --git a/src/mongo/shell/bench.h b/src/mongo/shell/bench.h
index 136e6825c2e..c335af687a1 100644
--- a/src/mongo/shell/bench.h
+++ b/src/mongo/shell/bench.h
@@ -96,6 +96,20 @@ public:
     BSONObj writeConcern;
     BSONObj value;
 
+    // Only used for find cmds when set greater than 0. A find operation will retrieve the latest
+    // cluster time from the oplog and randomly chooses a time between that timestamp and
+    // 'useClusterTimeWithinSeconds' seconds in the past at which to read.
+    //
+    // Must be used with 'useSnapshotReads=true' BenchRunConfig because atClusterTime is only
+    // allowed within a transaction.
+    int useAClusterTimeWithinPastSeconds = 0;
+
+    // Delays getMore commands following a find cmd. A uniformly distributed random value between 0
+    // and maxRandomMillisecondDelayBeforeGetMore will be generated for each getMore call. Useful
+    // for keeping a snapshot read open for a longer time duration, say to simulate the basic
+    // resources that a snapshot transaction would hold for a time.
+    int maxRandomMillisecondDelayBeforeGetMore{0};
+
     // This is an owned copy of the raw operation. All unowned members point into this.
     BSONObj myBsonOp;
 };
@@ -172,6 +186,11 @@ public:
      */
     bool useSnapshotReads{false};
 
+    /**
+     * How many milliseconds to sleep for if an operation fails, before continuing to the next op.
+     */
+    Milliseconds delayMillisOnFailedOperation{0};
+
     /// Base random seed for threads
     int64_t randomSeed;
 
@@ -221,6 +240,10 @@ public:
      * Count one instance of the event, which took "timeMicros" microseconds.
      */
     void countOne(long long timeMicros) {
+        if (_numEvents == std::numeric_limits<long long>::max()) {
+            fassertFailedWithStatus(50874,
+                                    {ErrorCodes::Overflow, "Overflowed the events counter."});
+        }
         ++_numEvents;
         _totalTimeMicros += timeMicros;
     }
@@ -235,13 +258,13 @@ public:
     /**
      * Get the number of observed events.
      */
-    unsigned long long getNumEvents() const {
+    long long getNumEvents() const {
         return _numEvents;
     }
 
 private:
     long long _totalTimeMicros{0};
-    unsigned long long _numEvents{0};
+    long long _numEvents{0};
 };
 
 /**
@@ -455,7 +478,7 @@ private:
 
     BenchRunState& _brState;
 
-    const int64_t _randomSeed;
+    PseudoRandom _rng;
 
     // Dummy stats to use before observation period.
     BenchRunStats _statsBlackHole;