SERVER-58533 Log FCV at initialization and on log rotation

3 files changed, 22 insertions, 2 deletions

diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index d8e768eba5a..7798cd2d2a6 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -421,6 +421,7 @@ void FeatureCompatibilityVersion::initializeForStartup(OperationContext* opCtx)
     invariant(opCtx->lockState()->isW());
     auto featureCompatibilityVersion = findFeatureCompatibilityVersionDocument(opCtx);
     if (!featureCompatibilityVersion) {
+        LOGV2(5853303, "featureCompatibilityVersion document missing at startup");
         return;
     }
 
@@ -437,8 +438,9 @@ void FeatureCompatibilityVersion::initializeForStartup(OperationContext* opCtx)
                              << "UPGRADE PROBLEM: Found an invalid featureCompatibilityVersion "
                                 "document (ERROR: "
                              << swVersion.getStatus()
-                             << "). If the current featureCompatibilityVersion is below 4.4, see "
-                                "the documentation on upgrading at "
+                             << "). If the current featureCompatibilityVersion is below "
+                             << multiversion::toString(multiversion::GenericFCV::kLastLTS)
+                             << ", see the documentation on upgrading at "
                              << feature_compatibility_version_documentation::kUpgradeLink << "."});
     }
 
@@ -446,6 +448,11 @@ void FeatureCompatibilityVersion::initializeForStartup(OperationContext* opCtx)
     serverGlobalParams.mutableFeatureCompatibility.setVersion(version);
     FeatureCompatibilityVersion::updateMinWireVersion();
 
+    LOGV2(5853300,
+          "Intializing featureCompatibilityVersion at startup",
+          "featureCompatibilityVersion"_attr =
+              multiversion::toString(serverGlobalParams.featureCompatibility.getVersion()));
+
     // On startup, if the version is in an upgrading or downgrading state, print a warning.
     if (serverGlobalParams.featureCompatibility.isUpgradingOrDowngrading()) {
         LOGV2_WARNING_OPTIONS(
diff --git a/src/mongo/db/log_process_details.cpp b/src/mongo/db/log_process_details.cpp
index 054b85ae6f5..16e70222266 100644
--- a/src/mongo/db/log_process_details.cpp
+++ b/src/mongo/db/log_process_details.cpp
@@ -103,6 +103,14 @@ void logProcessDetailsForLogRotate(ServiceContext* serviceContext) {
         }
     }
 
+    LOGV2(5853301,
+          "featureCompatibilityVersion on log rotation",
+          "featureCompatibilityVersion"_attr =
+              serverGlobalParams.featureCompatibility.isVersionInitialized()
+              ? multiversion::toString(serverGlobalParams.featureCompatibility.getVersion())
+              : multiversion::toString(
+                    multiversion::FeatureCompatibilityVersion::kUnsetDefaultLastLTSBehavior));
+
     logProcessDetails(nullptr);
 }
 
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index b28e2c4e1cb..ded42849496 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -4416,6 +4416,11 @@ ReplicationCoordinatorImpl::_updateMemberStateFromTopologyCoordinator(WithLock l
         // (Generic FCV reference): This FCV check should exist across LTS binary versions.
         serverGlobalParams.mutableFeatureCompatibility.setVersion(
             multiversion::GenericFCV::kLatest);
+        LOGV2(5853302,
+              "Update featureCompatibilityVersion because arbiters do not receive the replicated "
+              "version",
+              "featureCompatibilityVersion"_attr =
+                  multiversion::toString(serverGlobalParams.featureCompatibility.getVersion()));
     }
 
     _memberState = newState;