SERVER-47577: readConcernCounters metric in serverStatus

12 files changed, 149 insertions, 37 deletions

diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 37f85f0bd05..609371c6071 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -382,6 +382,14 @@ public:
     }
 
     /**
+     * Override and return true if the readConcernCounters in serverStatus should not be incremented
+     * on behalf of this command.
+     */
+    virtual bool shouldAffectReadConcernCounter() const {
+        return false;
+    }
+
+    /**
      * Return true if the command requires auth.
      */
     virtual bool requiresAuth() const {
diff --git a/src/mongo/db/commands/count_cmd.cpp b/src/mongo/db/commands/count_cmd.cpp
index 3063da6955b..aab21671ba9 100644
--- a/src/mongo/db/commands/count_cmd.cpp
+++ b/src/mongo/db/commands/count_cmd.cpp
@@ -94,6 +94,10 @@ public:
         return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     bool supportsReadMirroring(const BSONObj&) const override {
         return true;
     }
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 0d3c2318bff..964edb9dcb6 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -93,6 +93,10 @@ public:
         return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     bool supportsReadMirroring(const BSONObj&) const override {
         return true;
     }
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index d83db1ac6e2..de42810ba9b 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -169,6 +169,10 @@ public:
         return false;
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     class Invocation final : public CommandInvocation {
     public:
         Invocation(const FindCmd* definition, const OpMsgRequest& request, StringData dbName)
@@ -301,8 +305,6 @@ public:
             CommandHelpers::handleMarkKillOnClientDisconnect(opCtx);
             // Although it is a command, a find command gets counted as a query.
             globalOpCounters.gotQuery();
-            ServerReadConcernMetrics::get(opCtx)->recordReadConcern(
-                repl::ReadConcernArgs::get(opCtx));
 
             // Parse the command BSON to a QueryRequest. Pass in the parsedNss in case _request.body
             // does not have a UUID.
diff --git a/src/mongo/db/commands/haystack.cpp b/src/mongo/db/commands/haystack.cpp
index 93d3df3ff65..2346e048772 100644
--- a/src/mongo/db/commands/haystack.cpp
+++ b/src/mongo/db/commands/haystack.cpp
@@ -85,6 +85,10 @@ public:
         return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     ReadWriteType getReadWriteType() const {
         return ReadWriteType::kRead;
     }
diff --git a/src/mongo/db/commands/map_reduce_command_base.h b/src/mongo/db/commands/map_reduce_command_base.h
index a1c45276634..bcc0870dfe5 100644
--- a/src/mongo/db/commands/map_reduce_command_base.h
+++ b/src/mongo/db/commands/map_reduce_command_base.h
@@ -62,6 +62,10 @@ public:
                 {kDefaultReadConcernNotPermitted}};
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
         return map_reduce_common::mrSupportsWriteConcern(cmd);
     }
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index ebc251e65ea..915457281fe 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -78,6 +78,10 @@ public:
             this, opMsgRequest, std::move(aggregationRequest), std::move(privileges));
     }
 
+    bool shouldAffectReadConcernCounter() const override {
+        return true;
+    }
+
     class Invocation final : public CommandInvocation {
     public:
         Invocation(Command* cmd,
diff --git a/src/mongo/db/repl/read_concern_args.h b/src/mongo/db/repl/read_concern_args.h
index 04a2c3e131a..bdc3c5bf4eb 100644
--- a/src/mongo/db/repl/read_concern_args.h
+++ b/src/mongo/db/repl/read_concern_args.h
@@ -185,8 +185,18 @@ public:
     void setArgsAtClusterTimeForSnapshot(Timestamp ts) {
         invariant(_level && _level == ReadConcernLevel::kSnapshotReadConcern);
         invariant(!_atClusterTime);
+        invariant(!_atClusterTimeSelected);
         _afterClusterTime = boost::none;
         _atClusterTime = LogicalTime(ts);
+        _atClusterTimeSelected = true;
+    }
+
+    /**
+     * Return whether an atClusterTime has been selected by the server for a snapshot read. This
+     * function returns false if the atClusterTime was specified by the client.
+     */
+    bool wasAtClusterTimeSelected() const {
+        return _atClusterTimeSelected;
     }
 
 private:
@@ -223,6 +233,8 @@ private:
     bool _specified;
 
     ReadWriteConcernProvenance _provenance;
+
+    bool _atClusterTimeSelected = false;
 };
 
 }  // namespace repl
diff --git a/src/mongo/db/service_entry_point_common.cpp b/src/mongo/db/service_entry_point_common.cpp
index 55959347ec9..1e9f51a137a 100644
--- a/src/mongo/db/service_entry_point_common.cpp
+++ b/src/mongo/db/service_entry_point_common.cpp
@@ -615,13 +615,21 @@ void invokeWithSessionCheckedOut(OperationContext* opCtx,
     if (!opCtx->getClient()->isInDirectClient()) {
         const auto& readConcernArgs = repl::ReadConcernArgs::get(opCtx);
 
+        auto command = invocation->definition();
+        // Record readConcern usages for commands run inside transactions after unstashing the
+        // transaction resources.
+        if (command->shouldAffectReadConcernCounter() && opCtx->inMultiDocumentTransaction()) {
+            ServerReadConcernMetrics::get(opCtx)->recordReadConcern(readConcernArgs,
+                                                                    true /* isTransaction */);
+        }
+
         // For replica sets, we do not receive the readConcernArgs of our parent transaction
         // statements until we unstash the transaction resources. The below check is necessary to
         // ensure commands, including those occurring after the first statement in their respective
         // transactions, are checked for readConcern support. Presently, only `create` and
         // `createIndexes` do not support readConcern inside transactions.
         // TODO(SERVER-46971): Consider how to extend this check to other commands.
-        auto cmdName = invocation->definition()->getName();
+        auto cmdName = command->getName();
         auto readConcernSupport = invocation->supportsReadConcern(readConcernArgs.getLevel());
         if (readConcernArgs.hasLevel() &&
             (cmdName == "create"_sd || cmdName == "createIndexes"_sd)) {
@@ -714,6 +722,15 @@ bool runCommandImpl(OperationContext* opCtx,
     const bool shouldWaitForWriteConcern =
         invocation->supportsWriteConcern() || command->getLogicalOp() == LogicalOp::opGetMore;
 
+    // Record readConcern usages for commands run outside of transactions, excluding DBDirectClient.
+    // For commands inside a transaction, they inherit the readConcern from the transaction. So we
+    // will record their readConcern usages after we have unstashed the transaction resources.
+    if (!opCtx->getClient()->isInDirectClient() && command->shouldAffectReadConcernCounter() &&
+        !opCtx->inMultiDocumentTransaction()) {
+        ServerReadConcernMetrics::get(opCtx)->recordReadConcern(repl::ReadConcernArgs::get(opCtx),
+                                                                false /* isTransaction */);
+    }
+
     if (shouldWaitForWriteConcern) {
         auto lastOpBeforeRun = repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
 
@@ -1436,7 +1453,11 @@ DbResponse receivedQuery(OperationContext* opCtx,
                          const ServiceEntryPointCommon::Hooks& behaviors) {
     invariant(!nss.isCommand());
     globalOpCounters.gotQuery();
-    ServerReadConcernMetrics::get(opCtx)->recordReadConcern(repl::ReadConcernArgs::get(opCtx));
+
+    if (!opCtx->getClient()->isInDirectClient()) {
+        ServerReadConcernMetrics::get(opCtx)->recordReadConcern(repl::ReadConcernArgs::get(opCtx),
+                                                                false /* isTransaction */);
+    }
 
     DbMessage d(m);
     QueryMessage q(d);
diff --git a/src/mongo/db/stats/read_concern_stats.idl b/src/mongo/db/stats/read_concern_stats.idl
index 60636cf0c08..30ec3c47a05 100644
--- a/src/mongo/db/stats/read_concern_stats.idl
+++ b/src/mongo/db/stats/read_concern_stats.idl
@@ -38,26 +38,45 @@ imports:
 
 structs:
 
-  ReadConcernStats:
-    description: "A struct representing the section of the server status
-                  command with information about readConcern levels used by operations"
+  SnapshotOps:
+    description: "A struct representing the number of operations used with snapshot readConcern"
     strict: true
     fields:
-      available:
+      withClusterTime:
         type: long
         default: 0
-      linearizable:
+      withoutClusterTime:
+        type: long
+        default: 0
+
+  ReadConcernOps:
+    description: "A struct representing readConcern level usages by read operations"
+    strict: true
+    fields:
+      none:
         type: long
         default: 0
       local:
         type: long
         default: 0
+      available:
+        type: long
+        optional: true
       majority:
         type: long
         default: 0
       snapshot:
+        type: SnapshotOps
+      linearizable:
         type: long
-        default: 0
-      none:
-        type: long
-        default: 0
+        optional: true
+
+  ReadConcernStats:
+    description: "A struct representing the section of the server status
+                  command with information about readConcern levels used by operations"
+    strict: true
+    fields:
+      nonTransactionOps:
+        type: ReadConcernOps
+      transactionOps:
+        type: ReadConcernOps
diff --git a/src/mongo/db/stats/server_read_concern_metrics.cpp b/src/mongo/db/stats/server_read_concern_metrics.cpp
index 1dd4c9fff8e..a29b7ab781a 100644
--- a/src/mongo/db/stats/server_read_concern_metrics.cpp
+++ b/src/mongo/db/stats/server_read_concern_metrics.cpp
@@ -50,31 +50,41 @@ ServerReadConcernMetrics* ServerReadConcernMetrics::get(OperationContext* opCtx)
     return get(opCtx->getServiceContext());
 }
 
-void ServerReadConcernMetrics::recordReadConcern(const repl::ReadConcernArgs& readConcernArgs) {
+void ServerReadConcernMetrics::recordReadConcern(const repl::ReadConcernArgs& readConcernArgs,
+                                                 bool isTransaction) {
+    auto& ops = isTransaction ? _transactionOps : _nonTransactionOps;
+
     if (!readConcernArgs.hasLevel()) {
-        _noLevelCount.fetchAndAdd(1);
+        ops.noLevelCount.fetchAndAdd(1);
         return;
     }
 
     switch (readConcernArgs.getLevel()) {
         case repl::ReadConcernLevel::kAvailableReadConcern:
-            _levelAvailableCount.fetchAndAdd(1);
+            invariant(!isTransaction);
+            ops.levelAvailableCount.fetchAndAdd(1);
             break;
 
         case repl::ReadConcernLevel::kLinearizableReadConcern:
-            _levelLinearizableCount.fetchAndAdd(1);
+            invariant(!isTransaction);
+            ops.levelLinearizableCount.fetchAndAdd(1);
             break;
 
         case repl::ReadConcernLevel::kLocalReadConcern:
-            _levelLocalCount.fetchAndAdd(1);
+            ops.levelLocalCount.fetchAndAdd(1);
             break;
 
         case repl::ReadConcernLevel::kMajorityReadConcern:
-            _levelMajorityCount.fetchAndAdd(1);
+            ops.levelMajorityCount.fetchAndAdd(1);
             break;
 
         case repl::ReadConcernLevel::kSnapshotReadConcern:
-            _levelSnapshotCount.fetchAndAdd(1);
+            if (readConcernArgs.getArgsAtClusterTime() &&
+                !readConcernArgs.wasAtClusterTimeSelected()) {
+                ops.atClusterTimeCount.fetchAndAdd(1);
+            } else {
+                ops.levelSnapshotCount.fetchAndAdd(1);
+            }
             break;
 
         default:
@@ -83,20 +93,35 @@ void ServerReadConcernMetrics::recordReadConcern(const repl::ReadConcernArgs& re
 }
 
 void ServerReadConcernMetrics::updateStats(ReadConcernStats* stats, OperationContext* opCtx) {
-    stats->setAvailable(_levelAvailableCount.load());
-    stats->setLinearizable(_levelLinearizableCount.load());
-    stats->setLocal(_levelLocalCount.load());
-    stats->setMajority(_levelMajorityCount.load());
-    stats->setSnapshot(_levelSnapshotCount.load());
-    stats->setNone(_noLevelCount.load());
+    ReadConcernOps nonTransactionOps;
+    SnapshotOps nonTransactionSnapshotOps;
+    nonTransactionSnapshotOps.setWithoutClusterTime(_nonTransactionOps.levelSnapshotCount.load());
+    nonTransactionSnapshotOps.setWithClusterTime(_nonTransactionOps.atClusterTimeCount.load());
+    nonTransactionOps.setNone(_nonTransactionOps.noLevelCount.load());
+    nonTransactionOps.setAvailable(_nonTransactionOps.levelAvailableCount.load());
+    nonTransactionOps.setLinearizable(_nonTransactionOps.levelLinearizableCount.load());
+    nonTransactionOps.setLocal(_nonTransactionOps.levelLocalCount.load());
+    nonTransactionOps.setMajority(_nonTransactionOps.levelMajorityCount.load());
+    nonTransactionOps.setSnapshot(nonTransactionSnapshotOps);
+    stats->setNonTransactionOps(nonTransactionOps);
+
+    ReadConcernOps transactionOps;
+    SnapshotOps transactionSnapshotOps;
+    transactionSnapshotOps.setWithoutClusterTime(_transactionOps.levelSnapshotCount.load());
+    transactionSnapshotOps.setWithClusterTime(_transactionOps.atClusterTimeCount.load());
+    transactionOps.setNone(_transactionOps.noLevelCount.load());
+    transactionOps.setLocal(_transactionOps.levelLocalCount.load());
+    transactionOps.setMajority(_transactionOps.levelMajorityCount.load());
+    transactionOps.setSnapshot(transactionSnapshotOps);
+    stats->setTransactionOps(transactionOps);
 }
 
 namespace {
-class OpReadConcernCountersSSS : public ServerStatusSection {
+class ReadConcernCountersSSS : public ServerStatusSection {
 public:
-    OpReadConcernCountersSSS() : ServerStatusSection("opReadConcernCounters") {}
+    ReadConcernCountersSSS() : ServerStatusSection("readConcernCounters") {}
 
-    ~OpReadConcernCountersSSS() override = default;
+    ~ReadConcernCountersSSS() override = default;
 
     bool includeByDefault() const override {
         return true;
@@ -109,7 +134,7 @@ public:
         return stats.toBSON();
     }
 
-} opReadConcernCountersSSS;
+} ReadConcernCountersSSS;
 }  // namespace
 
 }  // namespace mongo
diff --git a/src/mongo/db/stats/server_read_concern_metrics.h b/src/mongo/db/stats/server_read_concern_metrics.h
index 1a247f79df6..7782b959bfd 100644
--- a/src/mongo/db/stats/server_read_concern_metrics.h
+++ b/src/mongo/db/stats/server_read_concern_metrics.h
@@ -52,7 +52,7 @@ public:
     /**
      * Updates counter for the level of 'readConcernArgs'.
      */
-    void recordReadConcern(const repl::ReadConcernArgs& readConcernArgs);
+    void recordReadConcern(const repl::ReadConcernArgs& readConcernArgs, bool isTransaction);
 
     /**
      * Appends the accumulated stats to a readConcern stats object.
@@ -60,12 +60,17 @@ public:
     void updateStats(ReadConcernStats* stats, OperationContext* opCtx);
 
 private:
-    AtomicWord<unsigned long long> _levelAvailableCount{0};
-    AtomicWord<unsigned long long> _levelLinearizableCount{0};
-    AtomicWord<unsigned long long> _levelLocalCount{0};
-    AtomicWord<unsigned long long> _levelMajorityCount{0};
-    AtomicWord<unsigned long long> _levelSnapshotCount{0};
-    AtomicWord<unsigned long long> _noLevelCount{0};
+    struct readConcernCounters {
+        AtomicWord<unsigned long long> levelAvailableCount{0};
+        AtomicWord<unsigned long long> levelLinearizableCount{0};
+        AtomicWord<unsigned long long> levelLocalCount{0};
+        AtomicWord<unsigned long long> levelMajorityCount{0};
+        AtomicWord<unsigned long long> levelSnapshotCount{0};
+        AtomicWord<unsigned long long> atClusterTimeCount{0};
+        AtomicWord<unsigned long long> noLevelCount{0};
+    };
+    readConcernCounters _nonTransactionOps;
+    readConcernCounters _transactionOps;
 };
 
 }  // namespace mongo