SERVER-58989 Make timestamp required in DatabaseVersionBase IDL

41 files changed, 135 insertions, 266 deletions

diff --git a/src/mongo/db/s/balancer/balance_stats_test.cpp b/src/mongo/db/s/balancer/balance_stats_test.cpp
index 0bae93f1693..21d1f7c13f8 100644
--- a/src/mongo/db/s/balancer/balance_stats_test.cpp
+++ b/src/mongo/db/s/balancer/balance_stats_test.cpp
@@ -75,7 +75,7 @@ private:
     const NamespaceString _nss{"foo.bar"};
     const OID _epoch{OID::gen()};
     const ShardId _shardPrimary{"dummyShardPrimary"};
-    const DatabaseVersion _dbVersion{UUID::gen()};
+    const DatabaseVersion _dbVersion{UUID::gen(), Timestamp()};
     ChunkVersion _nextVersion{1, 0, _epoch, boost::none};
 };
 
diff --git a/src/mongo/db/s/balancer/migration_test_fixture.cpp b/src/mongo/db/s/balancer/migration_test_fixture.cpp
index 3320a43142d..7744c36d0a7 100644
--- a/src/mongo/db/s/balancer/migration_test_fixture.cpp
+++ b/src/mongo/db/s/balancer/migration_test_fixture.cpp
@@ -48,7 +48,7 @@ std::shared_ptr<RemoteCommandTargeterMock> MigrationTestFixture::shardTargeterMo
 }
 
 void MigrationTestFixture::setUpDatabase(const std::string& dbName, const ShardId primaryShard) {
-    DatabaseType db(dbName, primaryShard, true, DatabaseVersion(UUID::gen()));
+    DatabaseType db(dbName, primaryShard, true, DatabaseVersion(UUID::gen(), Timestamp()));
     ASSERT_OK(catalogClient()->insertConfigDocument(
         operationContext(), DatabaseType::ConfigNS, db.toBSON(), kMajorityWriteConcern));
 }
diff --git a/src/mongo/db/s/collection_metadata_filtering_test.cpp b/src/mongo/db/s/collection_metadata_filtering_test.cpp
index 0d10ba6de96..3bd22a6cded 100644
--- a/src/mongo/db/s/collection_metadata_filtering_test.cpp
+++ b/src/mongo/db/s/collection_metadata_filtering_test.cpp
@@ -110,7 +110,7 @@ protected:
             }());
 
         ChunkManager cm(ShardId("0"),
-                        DatabaseVersion(UUID::gen()),
+                        DatabaseVersion(UUID::gen(), Timestamp()),
                         makeStandaloneRoutingTableHistory(std::move(rt)),
                         boost::none);
         ASSERT_EQ(4, cm.numChunks());
diff --git a/src/mongo/db/s/collection_metadata_test.cpp b/src/mongo/db/s/collection_metadata_test.cpp
index b4e8e1231b5..1b7c31a3e8d 100644
--- a/src/mongo/db/s/collection_metadata_test.cpp
+++ b/src/mongo/db/s/collection_metadata_test.cpp
@@ -52,6 +52,7 @@ CollectionMetadata makeCollectionMetadataImpl(
     const std::vector<std::pair<BSONObj, BSONObj>>& thisShardsChunks,
     bool staleChunkManager,
     UUID uuid = UUID::gen(),
+    Timestamp timestamp = Timestamp(),
     boost::optional<TypeCollectionReshardingFields> reshardingFields = boost::none) {
 
     const OID epoch = OID::gen();
@@ -85,7 +86,7 @@ CollectionMetadata makeCollectionMetadataImpl(
 
     return CollectionMetadata(
         ChunkManager(kThisShard,
-                     DatabaseVersion(uuid),
+                     DatabaseVersion(uuid, timestamp),
                      ShardingTestFixtureCommon::makeStandaloneRoutingTableHistory(
                          RoutingTableHistory::makeNew(kNss,
                                                       uuid,
@@ -134,7 +135,7 @@ protected:
             (state >= CoordinatorStateEnum::kCommitting) ? reshardingUuid : existingUuid;
 
         return makeCollectionMetadataImpl(
-            KeyPattern(BSON("a" << 1)), {}, false, metadataUuid, reshardingFields);
+            KeyPattern(BSON("a" << 1)), {}, false, metadataUuid, Timestamp(), reshardingFields);
     }
 };
 
diff --git a/src/mongo/db/s/collection_sharding_runtime_test.cpp b/src/mongo/db/s/collection_sharding_runtime_test.cpp
index 52022ffd6a9..bf7de89a625 100644
--- a/src/mongo/db/s/collection_sharding_runtime_test.cpp
+++ b/src/mongo/db/s/collection_sharding_runtime_test.cpp
@@ -62,7 +62,7 @@ protected:
                                ChunkVersion(1, 0, epoch, boost::none /* timestamp */),
                                ShardId("other"));
         ChunkManager cm(ShardId("0"),
-                        DatabaseVersion(UUID::gen()),
+                        DatabaseVersion(UUID::gen(), Timestamp()),
                         makeStandaloneRoutingTableHistory(
                             RoutingTableHistory::makeNew(kTestNss,
                                                          uuid,
@@ -293,8 +293,10 @@ protected:
 
 TEST_F(CollectionShardingRuntimeTestWithMockedLoader,
        ForceShardFilteringMetadataRefreshWithUpdateMetadataFormat) {
-    const DatabaseType dbType(
-        kNss.db().toString(), kShardList[0].getName(), true, DatabaseVersion(UUID::gen()));
+    const DatabaseType dbType(kNss.db().toString(),
+                              kShardList[0].getName(),
+                              true,
+                              DatabaseVersion(UUID::gen(), Timestamp()));
 
     const auto epoch = OID::gen();
     const Timestamp timestamp(42);
@@ -329,8 +331,10 @@ TEST_F(CollectionShardingRuntimeTestWithMockedLoader,
 
 TEST_F(CollectionShardingRuntimeTestWithMockedLoader,
        OnShardVersionMismatchWithUpdateMetadataFormat) {
-    const DatabaseType dbType(
-        kNss.db().toString(), kShardList[0].getName(), true, DatabaseVersion(UUID::gen()));
+    const DatabaseType dbType(kNss.db().toString(),
+                              kShardList[0].getName(),
+                              true,
+                              DatabaseVersion(UUID::gen(), Timestamp()));
 
     const auto epoch = OID::gen();
     const Timestamp timestamp(42);
diff --git a/src/mongo/db/s/config/config_server_test_fixture.cpp b/src/mongo/db/s/config/config_server_test_fixture.cpp
index b97f1274455..ffd9c9b4baf 100644
--- a/src/mongo/db/s/config/config_server_test_fixture.cpp
+++ b/src/mongo/db/s/config/config_server_test_fixture.cpp
@@ -409,7 +409,7 @@ StatusWith<ChunkVersion> ConfigServerTestFixture::getCollectionVersion(Operation
 void ConfigServerTestFixture::setupDatabase(const std::string& dbName,
                                             const ShardId primaryShard,
                                             const bool sharded) {
-    DatabaseType db(dbName, primaryShard, sharded, DatabaseVersion(UUID::gen()));
+    DatabaseType db(dbName, primaryShard, sharded, DatabaseVersion(UUID::gen(), Timestamp()));
     ASSERT_OK(catalogClient()->insertConfigDocument(operationContext(),
                                                     DatabaseType::ConfigNS,
                                                     db.toBSON(),
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
index c9e7a0c81bd..e47bebc388c 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp
@@ -380,9 +380,9 @@ TEST_F(AddShardTest, StandaloneBasicSuccess) {
     expectedShard.setState(ShardType::ShardState::kShardAware);
 
     DatabaseType discoveredDB1(
-        "TestDB1", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen()));
+        "TestDB1", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen(), Timestamp()));
     DatabaseType discoveredDB2(
-        "TestDB2", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen()));
+        "TestDB2", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto expectWriteConcern = ShardingCatalogClient::kMajorityWriteConcern;
 
@@ -466,9 +466,9 @@ TEST_F(AddShardTest, StandaloneGenerateName) {
     expectedShard.setState(ShardType::ShardState::kShardAware);
 
     DatabaseType discoveredDB1(
-        "TestDB1", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen()));
+        "TestDB1", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen(), Timestamp()));
     DatabaseType discoveredDB2(
-        "TestDB2", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen()));
+        "TestDB2", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, &expectedShardName, &shardTarget] {
         ThreadClient tc(getServiceContext());
@@ -810,7 +810,7 @@ TEST_F(AddShardTest, ShardContainsExistingDatabase) {
     std::string expectedShardName = "mySet";
 
     DatabaseType existingDB(
-        "existing", ShardId("existingShard"), false, DatabaseVersion(UUID::gen()));
+        "existing", ShardId("existingShard"), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     // Add a pre-existing database.
     ASSERT_OK(catalogClient()->insertConfigDocument(operationContext(),
@@ -865,7 +865,7 @@ TEST_F(AddShardTest, SuccessfullyAddReplicaSet) {
     expectedShard.setState(ShardType::ShardState::kShardAware);
 
     DatabaseType discoveredDB(
-        "shardDB", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen()));
+        "shardDB", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, &expectedShardName, &connString] {
         ThreadClient tc(getServiceContext());
@@ -930,7 +930,7 @@ TEST_F(AddShardTest, ReplicaSetExtraHostsDiscovered) {
     expectedShard.setState(ShardType::ShardState::kShardAware);
 
     DatabaseType discoveredDB(
-        "shardDB", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen()));
+        "shardDB", ShardId(expectedShardName), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, &expectedShardName, &seedString] {
         ThreadClient tc(getServiceContext());
@@ -996,9 +996,9 @@ TEST_F(AddShardTest, AddShardSucceedsEvenIfAddingDBsFromNewShardFails) {
     expectedShard.setState(ShardType::ShardState::kShardAware);
 
     DatabaseType discoveredDB1(
-        "TestDB1", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen()));
+        "TestDB1", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen(), Timestamp()));
     DatabaseType discoveredDB2(
-        "TestDB2", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen()));
+        "TestDB2", ShardId("StandaloneShard"), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     // Enable fail point to cause all updates to fail.  Since we add the databases detected from
     // the shard being added with upserts, but we add the shard document itself via insert, this
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
index 0a0d1157987..8434c02eeaa 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
@@ -34,13 +34,11 @@
 #include <pcrecpp.h>
 
 #include "mongo/bson/util/bson_extract.h"
-#include "mongo/db/commands/feature_compatibility_version.h"
 #include "mongo/db/dbdirectclient.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/ops/write_ops.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/s/dist_lock_manager.h"
-#include "mongo/db/s/sharding_ddl_50_upgrade_downgrade.h"
 #include "mongo/db/server_options.h"
 #include "mongo/db/vector_clock.h"
 #include "mongo/db/write_concern.h"
@@ -199,13 +197,8 @@ DatabaseType ShardingCatalogManager::createDatabase(OperationContext* opCtx,
                 optPrimaryShard ? *optPrimaryShard
                                 : selectShardForNewDatabase(opCtx, shardRegistry)));
 
-            FixedFCVRegion fcvRegion(opCtx);
-
-            boost::optional<Timestamp> clusterTime;
-            if (DatabaseEntryFormat::get(fcvRegion) == DatabaseEntryFormat::kUUIDandTimestamp) {
-                const auto now = VectorClock::get(opCtx)->getTime();
-                clusterTime = now.clusterTime().asTimestamp();
-            }
+            const auto now = VectorClock::get(opCtx)->getTime();
+            const auto clusterTime = now.clusterTime().asTimestamp();
 
             // Pick a primary shard for the new database.
             DatabaseType db(dbName.toString(),
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
index 669ff694087..5be30965ad4 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_shard_operations.cpp
@@ -59,7 +59,6 @@
 #include "mongo/db/repl/repl_set_config.h"
 #include "mongo/db/s/add_shard_cmd_gen.h"
 #include "mongo/db/s/add_shard_util.h"
-#include "mongo/db/s/sharding_ddl_50_upgrade_downgrade.h"
 #include "mongo/db/s/sharding_logging.h"
 #include "mongo/db/s/type_shard_identity.h"
 #include "mongo/db/vector_clock_mutable.h"
@@ -745,11 +744,8 @@ StatusWith<std::string> ShardingCatalogManager::addShard(
 
         // Add all databases which were discovered on the new shard
         for (const auto& dbName : dbNamesStatus.getValue()) {
-            boost::optional<Timestamp> clusterTime;
-            if (DatabaseEntryFormat::get(fcvRegion) == DatabaseEntryFormat::kUUIDandTimestamp) {
-                const auto now = VectorClock::get(opCtx)->getTime();
-                clusterTime = now.clusterTime().asTimestamp();
-            }
+            const auto now = VectorClock::get(opCtx)->getTime();
+            const auto clusterTime = now.clusterTime().asTimestamp();
 
             DatabaseType dbt(
                 dbName, shardType.getName(), false, DatabaseVersion(UUID::gen(), clusterTime));
diff --git a/src/mongo/db/s/database_sharding_state_test.cpp b/src/mongo/db/s/database_sharding_state_test.cpp
index 4522c060433..007da2b6568 100644
--- a/src/mongo/db/s/database_sharding_state_test.cpp
+++ b/src/mongo/db/s/database_sharding_state_test.cpp
@@ -118,8 +118,7 @@ public:
         return std::make_unique<StaticCatalogClient>(kShardList);
     }
 
-    DatabaseType createDatabase(const UUID& uuid,
-                                boost::optional<Timestamp> timestamp = boost::none) {
+    DatabaseType createDatabase(const UUID& uuid, const Timestamp& timestamp) {
         return DatabaseType(
             kDbName.toString(), kShardList[0].getName(), true, DatabaseVersion(uuid, timestamp));
     }
@@ -129,10 +128,10 @@ protected:
 };
 
 TEST_F(DatabaseShardingStateTestWithMockedLoader, OnDbVersionMismatch) {
-    const auto oldDb = createDatabase(UUID::gen());
-    const auto newDb = createDatabase(UUID::gen());
+    const auto oldDb = createDatabase(UUID::gen(), Timestamp(1));
+    const auto newDb = createDatabase(UUID::gen(), Timestamp(2));
 
-    auto checkOnDbVersionMismatch = [&](const auto& newDb) {
+    auto checkOnDbVersionMismatch = [&](const auto& newDb, bool expectRefresh) {
         const auto newDbVersion = newDb.getVersion();
         auto opCtx = operationContext();
 
@@ -150,56 +149,23 @@ TEST_F(DatabaseShardingStateTestWithMockedLoader, OnDbVersionMismatch) {
 
         activeDbVersion = getActiveDbVersion();
         ASSERT_TRUE(activeDbVersion);
-        ASSERT_EQ(newDbVersion.getTimestamp(), activeDbVersion->getTimestamp());
-    };
-
-    checkOnDbVersionMismatch(oldDb);
-    checkOnDbVersionMismatch(newDb);
-    checkOnDbVersionMismatch(oldDb);
-}
-
-TEST_F(DatabaseShardingStateTestWithMockedLoader, OnDbVersionMismatchWithUpdateMetadataFormat) {
-    const auto uuid = UUID::gen();
-    const Timestamp timestamp(42);
-
-    const auto db = createDatabase(uuid);
-    const auto timestampedDb = createDatabase(uuid, timestamp);
-
-    auto checkOnDbVersionMismatch = [&](const auto& newDb) {
-        auto opCtx = operationContext();
-
-        _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(newDb);
-
-        auto getActiveDbVersion = [&] {
-            AutoGetDb autoDb(opCtx, kDbName, MODE_IS);
-            const auto dss = DatabaseShardingState::get(opCtx, kDbName);
-            auto dssLock = DatabaseShardingState::DSSLock::lockShared(opCtx, dss);
-            return dss->getDbVersion(opCtx, dssLock);
-        };
-
-        boost::optional<DatabaseVersion> activeDbVersion = getActiveDbVersion();
-
-        const auto& newDbVersion = newDb.getVersion();
-        ASSERT_OK(onDbVersionMismatchNoExcept(opCtx, kDbName, newDbVersion, activeDbVersion));
-
-        activeDbVersion = getActiveDbVersion();
-        ASSERT_TRUE(activeDbVersion);
-        ASSERT_EQ(newDbVersion.getTimestamp(), activeDbVersion->getTimestamp());
+        if (expectRefresh) {
+            ASSERT_EQUALS(newDbVersion.getTimestamp(), activeDbVersion->getTimestamp());
+        }
     };
 
-    checkOnDbVersionMismatch(db);
-    checkOnDbVersionMismatch(timestampedDb);
-    checkOnDbVersionMismatch(db);
+    checkOnDbVersionMismatch(oldDb, true);
+    checkOnDbVersionMismatch(newDb, true);
+    checkOnDbVersionMismatch(oldDb, false);
 }
 
-TEST_F(DatabaseShardingStateTestWithMockedLoader, ForceDatabaseRefreshWithUpdateMetadataFormat) {
+TEST_F(DatabaseShardingStateTestWithMockedLoader, ForceDatabaseRefresh) {
     const auto uuid = UUID::gen();
-    const Timestamp timestamp(42);
 
-    const auto db = createDatabase(uuid);
-    const auto timestampedDb = createDatabase(uuid, timestamp);
+    const auto oldDb = createDatabase(uuid, Timestamp(1));
+    const auto newDb = createDatabase(uuid, Timestamp(2));
 
-    auto checkForceDatabaseRefresh = [&](const auto& newDb) {
+    auto checkForceDatabaseRefresh = [&](const auto& newDb, bool expectRefresh) {
         const auto newDbVersion = newDb.getVersion();
         auto opCtx = operationContext();
 
@@ -213,12 +179,14 @@ TEST_F(DatabaseShardingStateTestWithMockedLoader, ForceDatabaseRefreshWithUpdate
             return dss->getDbVersion(opCtx, dssLock);
         }();
         ASSERT_TRUE(activeDbVersion);
-        ASSERT_EQ(newDbVersion.getTimestamp(), activeDbVersion->getTimestamp());
+        if (expectRefresh) {
+            ASSERT_EQ(newDbVersion.getTimestamp(), activeDbVersion->getTimestamp());
+        }
     };
 
-    checkForceDatabaseRefresh(db);
-    checkForceDatabaseRefresh(timestampedDb);
-    checkForceDatabaseRefresh(db);
+    checkForceDatabaseRefresh(oldDb, true);
+    checkForceDatabaseRefresh(newDb, true);
+    checkForceDatabaseRefresh(oldDb, false);
 }
 
 }  // namespace
diff --git a/src/mongo/db/s/metadata_manager_test.cpp b/src/mongo/db/s/metadata_manager_test.cpp
index dc59cd318e4..3002cafe317 100644
--- a/src/mongo/db/s/metadata_manager_test.cpp
+++ b/src/mongo/db/s/metadata_manager_test.cpp
@@ -94,7 +94,7 @@ protected:
                 kNss, range, ChunkVersion(1, 0, epoch, boost::none /* timestamp */), kOtherShard}});
 
         return CollectionMetadata(ChunkManager(kThisShard,
-                                               DatabaseVersion(UUID::gen()),
+                                               DatabaseVersion(UUID::gen(), Timestamp()),
                                                makeStandaloneRoutingTableHistory(std::move(rt)),
                                                boost::none),
                                   kThisShard);
diff --git a/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp b/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
index 8331d16be84..ffdf12f08c8 100644
--- a/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
+++ b/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
@@ -144,7 +144,7 @@ protected:
     }
 
     /**
-     * Creates a collection, which contains an index corresponding to kShardKeyPattern and insers
+     * Creates a collection, which contains an index corresponding to kShardKeyPattern and inserts
      * the specified initial documents.
      */
     void createShardedCollection(const std::vector<BSONObj>& initialDocs) {
@@ -187,7 +187,7 @@ protected:
                     operationContext(),
                     CollectionMetadata(
                         ChunkManager(ShardId("dummyShardId"),
-                                     DatabaseVersion(UUID::gen()),
+                                     DatabaseVersion(UUID::gen(), Timestamp()),
                                      makeStandaloneRoutingTableHistory(std::move(rt)),
                                      boost::none),
                         ShardId("dummyShardId")));
diff --git a/src/mongo/db/s/migration_util_test.cpp b/src/mongo/db/s/migration_util_test.cpp
index 48ca52613fc..3c50b5eab20 100644
--- a/src/mongo/db/s/migration_util_test.cpp
+++ b/src/mongo/db/s/migration_util_test.cpp
@@ -350,8 +350,9 @@ public:
     const ShardKeyPattern kShardKeyPattern = ShardKeyPattern(BSON("_id" << 1));
     const UUID kDefaultUUID = UUID::gen();
     const OID kEpoch = OID::gen();
-    const DatabaseType kDefaultDatabaseType =
-        DatabaseType(kNss.db().toString(), ShardId("0"), true, DatabaseVersion(kDefaultUUID));
+    const Timestamp kDefaultTimestamp = Timestamp();
+    const DatabaseType kDefaultDatabaseType = DatabaseType(
+        kNss.db().toString(), ShardId("0"), true, DatabaseVersion(kDefaultUUID, kDefaultTimestamp));
     const std::vector<ShardType> kShardList = {ShardType("0", "Host0:12345"),
                                                ShardType("1", "Host1:12345")};
 
diff --git a/src/mongo/db/s/op_observer_sharding_test.cpp b/src/mongo/db/s/op_observer_sharding_test.cpp
index 9f67cb2c930..076f4d8ee82 100644
--- a/src/mongo/db/s/op_observer_sharding_test.cpp
+++ b/src/mongo/db/s/op_observer_sharding_test.cpp
@@ -82,7 +82,7 @@ protected:
                                                {std::move(chunk)});
 
         return CollectionMetadata(ChunkManager(ShardId("this"),
-                                               DatabaseVersion(UUID::gen()),
+                                               DatabaseVersion(UUID::gen(), Timestamp()),
                                                makeStandaloneRoutingTableHistory(std::move(rt)),
                                                Timestamp(100, 0)),
                                   ShardId("this"));
diff --git a/src/mongo/db/s/operation_sharding_state.cpp b/src/mongo/db/s/operation_sharding_state.cpp
index 1280a50e9a6..66a91cdb2b1 100644
--- a/src/mongo/db/s/operation_sharding_state.cpp
+++ b/src/mongo/db/s/operation_sharding_state.cpp
@@ -102,8 +102,8 @@ void OperationShardingState::initializeClientRoutingVersions(
         }
     }
     if (dbVersion) {
-        invariant(_databaseVersions.find(nss.db()) == _databaseVersions.end());
-        _databaseVersions[nss.db()] = *dbVersion;
+        const auto [_, inserted] = _databaseVersions.emplace(nss.db(), *dbVersion);
+        invariant(inserted);
     }
 }
 
diff --git a/src/mongo/db/s/range_deletion_util_test.cpp b/src/mongo/db/s/range_deletion_util_test.cpp
index f4300ae3a2c..1b0e75d6327 100644
--- a/src/mongo/db/s/range_deletion_util_test.cpp
+++ b/src/mongo/db/s/range_deletion_util_test.cpp
@@ -121,7 +121,7 @@ public:
             ->setFilteringMetadata(
                 operationContext(),
                 CollectionMetadata(ChunkManager(ShardId("dummyShardId"),
-                                                DatabaseVersion(UUID::gen()),
+                                                DatabaseVersion(UUID::gen(), Timestamp()),
                                                 makeStandaloneRoutingTableHistory(std::move(rt)),
                                                 boost::none),
                                    ShardId("dummyShardId")));
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
index 638075c34f3..234d148641d 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
@@ -387,7 +387,7 @@ public:
         DatabaseType dbDoc(coordinatorDoc.getSourceNss().db().toString(),
                            coordinatorDoc.getDonorShards().front().getId(),
                            true,
-                           DatabaseVersion{UUID::gen()});
+                           DatabaseVersion{UUID::gen(), Timestamp()});
         client.insert(DatabaseType::ConfigNS.ns(), dbDoc.toBSON());
 
         return coordinatorDoc;
diff --git a/src/mongo/db/s/resharding/resharding_data_replication_test.cpp b/src/mongo/db/s/resharding/resharding_data_replication_test.cpp
index a911af349f7..9e8b4d1c3e1 100644
--- a/src/mongo/db/s/resharding/resharding_data_replication_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_data_replication_test.cpp
@@ -92,7 +92,7 @@ public:
                                                chunks);
 
         return ChunkManager(_myDonorId,
-                            DatabaseVersion(UUID::gen()),
+                            DatabaseVersion(UUID::gen(), Timestamp()),
                             makeStandaloneRoutingTableHistory(std::move(rt)),
                             boost::none /* clusterTime */);
     }
diff --git a/src/mongo/db/s/resharding/resharding_donor_recipient_common_test.h b/src/mongo/db/s/resharding/resharding_donor_recipient_common_test.h
index 499ff3a5301..858cdc4643c 100644
--- a/src/mongo/db/s/resharding/resharding_donor_recipient_common_test.h
+++ b/src/mongo/db/s/resharding/resharding_donor_recipient_common_test.h
@@ -51,6 +51,7 @@ using namespace fmt::literals;
 class ReshardingDonorRecipientCommonInternalsTest : public ShardServerTestFixture {
 public:
     const UUID kExistingUUID = UUID::gen();
+    const Timestamp kExistingTimestamp = Timestamp();
     const NamespaceString kOriginalNss = NamespaceString("db", "foo");
 
     const NamespaceString kTemporaryReshardingNss =
@@ -62,6 +63,7 @@ public:
     const OID kOriginalEpoch = OID::gen();
     const OID kReshardingEpoch = OID::gen();
     const UUID kReshardingUUID = UUID::gen();
+    const Timestamp kReshardingTimestamp = Timestamp(kExistingTimestamp.getSecs() + 1, 0);
 
     const DonorShardFetchTimestamp kThisShard =
         makeDonorShardFetchTimestamp(ShardId("shardOne"), Timestamp(10, 0));
@@ -80,6 +82,7 @@ protected:
                                    kOriginalShardKey,
                                    kOriginalShardKeyPattern,
                                    kExistingUUID,
+                                   kExistingTimestamp,
                                    kOriginalEpoch,
                                    shardThatChunkExistsOn);
     }
@@ -91,6 +94,7 @@ protected:
                                    kReshardingKey,
                                    kReshardingKeyPattern,
                                    kReshardingUUID,
+                                   kReshardingTimestamp,
                                    kReshardingEpoch,
                                    shardThatChunkExistsOn);
     }
@@ -100,13 +104,14 @@ protected:
                                            const std::string& shardKey,
                                            const BSONObj& shardKeyPattern,
                                            const UUID& uuid,
+                                           const Timestamp& timestamp,
                                            const OID& epoch,
                                            const ShardId& shardThatChunkExistsOn) {
         auto range = ChunkRange(BSON(shardKey << MINKEY), BSON(shardKey << MAXKEY));
         auto chunk = ChunkType(
             nss, std::move(range), ChunkVersion(1, 0, epoch, boost::none), shardThatChunkExistsOn);
         ChunkManager cm(kThisShard.getShardId(),
-                        DatabaseVersion(uuid),
+                        DatabaseVersion(uuid, timestamp),
                         makeStandaloneRoutingTableHistory(
                             RoutingTableHistory::makeNew(nss,
                                                          uuid,
diff --git a/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp b/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
index ef205fbd7fe..b503567685b 100644
--- a/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
@@ -197,7 +197,7 @@ public:
                                                chunks);
 
         return ChunkManager(_sourceId.getShardId(),
-                            DatabaseVersion(UUID::gen()),
+                            DatabaseVersion(UUID::gen(), Timestamp()),
                             makeStandaloneRoutingTableHistory(std::move(rt)),
                             boost::none);
     }
diff --git a/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp b/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
index 88160624032..c97b47ffce8 100644
--- a/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
@@ -306,7 +306,7 @@ private:
                                                chunks);
 
         return ChunkManager(_myDonorId,
-                            DatabaseVersion(UUID::gen()),
+                            DatabaseVersion(UUID::gen(), Timestamp()),
                             makeStandaloneRoutingTableHistory(std::move(rt)),
                             boost::none /* clusterTime */);
     }
diff --git a/src/mongo/db/s/resharding/resharding_oplog_crud_application_test.cpp b/src/mongo/db/s/resharding/resharding_oplog_crud_application_test.cpp
index b155330628d..b933e609fc1 100644
--- a/src/mongo/db/s/resharding/resharding_oplog_crud_application_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_oplog_crud_application_test.cpp
@@ -268,7 +268,7 @@ private:
                                                chunks);
 
         return ChunkManager(_myDonorId,
-                            DatabaseVersion(UUID::gen()),
+                            DatabaseVersion(UUID::gen(), Timestamp()),
                             makeStandaloneRoutingTableHistory(std::move(rt)),
                             boost::none /* clusterTime */);
     }
diff --git a/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp b/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
index ba38767c4be..074a5f74aaa 100644
--- a/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
@@ -203,10 +203,10 @@ public:
     void expectStaleDbVersionError(const NamespaceString& nss, StringData expectedCmdName) {
         onCommand([&](const executor::RemoteCommandRequest& request) {
             ASSERT_EQ(request.cmdObj.firstElementFieldNameStringData(), expectedCmdName);
-            return createErrorCursorResponse(
-                Status(StaleDbRoutingVersion(
-                           nss.db().toString(), DatabaseVersion(UUID::gen()), boost::none),
-                       "dummy stale db version error"));
+            return createErrorCursorResponse(Status(
+                StaleDbRoutingVersion(
+                    nss.db().toString(), DatabaseVersion(UUID::gen(), Timestamp()), boost::none),
+                "dummy stale db version error"));
         });
     }
 
diff --git a/src/mongo/db/s/resharding/resharding_recipient_service_test.cpp b/src/mongo/db/s/resharding/resharding_recipient_service_test.cpp
index 5dbe89aab0b..481d04a3556 100644
--- a/src/mongo/db/s/resharding/resharding_recipient_service_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_recipient_service_test.cpp
@@ -97,7 +97,7 @@ public:
                                                chunks);
 
         return ChunkManager(_someDonorId,
-                            DatabaseVersion(UUID::gen()),
+                            DatabaseVersion(UUID::gen(), Timestamp()),
                             _makeStandaloneRoutingTableHistory(std::move(rt)),
                             boost::none /* clusterTime */);
     }
diff --git a/src/mongo/db/s/resharding_destined_recipient_test.cpp b/src/mongo/db/s/resharding_destined_recipient_test.cpp
index 26eb6ca32d0..362a88e9c30 100644
--- a/src/mongo/db/s/resharding_destined_recipient_test.cpp
+++ b/src/mongo/db/s/resharding_destined_recipient_test.cpp
@@ -178,7 +178,7 @@ protected:
         UUID sourceUuid;
         ShardId destShard;
         ChunkVersion version;
-        DatabaseVersion dbVersion;
+        DatabaseVersion dbVersion{UUID::gen(), Timestamp()};
     };
 
     ReshardingEnv setupReshardingEnv(OperationContext* opCtx, bool refreshTempNss) {
@@ -196,7 +196,6 @@ protected:
         ReshardingEnv env(CollectionCatalog::get(opCtx)->lookupUUIDByNSS(opCtx, kNss).value());
         env.destShard = kShardList[1].getName();
         env.version = ChunkVersion(1, 0, OID::gen(), boost::none /* timestamp */);
-        env.dbVersion = DatabaseVersion(UUID::gen());
         env.tempNss =
             NamespaceString(kNss.db(),
                             fmt::format("{}{}",
diff --git a/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp b/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
index 9f4443d8069..09ed06890cf 100644
--- a/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
+++ b/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
@@ -440,7 +440,7 @@ TEST_F(ShardServerCatalogCacheLoaderTest, PrimaryLoadFromShardedAndFindMixedChun
 
 TEST_F(ShardServerCatalogCacheLoaderTest, PrimaryLoadFromShardedAndFindDbMetadataFormatChanged) {
     const std::string dbName("dbName");
-    DatabaseVersion version(UUID::gen());
+    DatabaseVersion version(UUID::gen(), Timestamp());
     DatabaseType dbType(dbName, kShardId, true /* sharded */, version);
 
     _remoteLoaderMock->setDatabaseRefreshReturnValue(dbType);
diff --git a/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.cpp b/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.cpp
index d372eb4d47a..254ed55ad68 100644
--- a/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.cpp
+++ b/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.cpp
@@ -36,21 +36,6 @@ namespace mongo {
 using FeatureCompatibility = ServerGlobalParams::FeatureCompatibility;
 using FCVersion = FeatureCompatibility::Version;
 
-DatabaseEntryFormat::Format DatabaseEntryFormat::get(const FixedFCVRegion& fcvRegion) {
-    switch (fcvRegion->getVersion()) {
-        case FCVersion::kUpgradingFrom44To50:
-        case FCVersion::kUpgradingFrom49To50:
-        case FCVersion::kUpgradingFrom50To51:
-        case FCVersion::kDowngradingFrom51To50:
-        case FCVersion::kFullyDowngradedTo50:
-        case FCVersion::kVersion51:
-            return Format::kUUIDandTimestamp;
-
-        default:
-            return Format::kUUIDOnly;
-    }
-}
-
 ChunkEntryFormat::Format ChunkEntryFormat::get(const FixedFCVRegion& fcvRegion) {
     return getForVersionCallerGuaranteesFCVStability(fcvRegion->getVersion());
 }
diff --git a/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.h b/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.h
index 9383d0a6c8a..cb0c23ee63b 100644
--- a/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.h
+++ b/src/mongo/db/s/sharding_ddl_50_upgrade_downgrade.h
@@ -33,15 +33,6 @@
 
 namespace mongo {
 
-struct DatabaseEntryFormat {
-    enum Format {
-        kUUIDOnly,
-        kUUIDandTimestamp,
-    };
-
-    static Format get(const FixedFCVRegion& fcvRegion);
-};
-
 struct ChunkEntryFormat {
     enum Format {
         kNamespaceOnlyNoTimestamps,       // Chunks have ns, no timestamps in the version
diff --git a/src/mongo/s/build_versioned_requests_for_targeted_shards_test.cpp b/src/mongo/s/build_versioned_requests_for_targeted_shards_test.cpp
index accbd515922..f82794e31f3 100644
--- a/src/mongo/s/build_versioned_requests_for_targeted_shards_test.cpp
+++ b/src/mongo/s/build_versioned_requests_for_targeted_shards_test.cpp
@@ -73,7 +73,8 @@ protected:
 
     void expectGetDatabaseUnsharded() {
         expectFindSendBSONObjVector(kConfigHostAndPort, [&]() {
-            DatabaseType db(kNss.db().toString(), {"0"}, false, DatabaseVersion(UUID::gen()));
+            DatabaseType db(
+                kNss.db().toString(), {"0"}, false, DatabaseVersion(UUID::gen(), Timestamp()));
             return std::vector<BSONObj>{db.toBSON()};
         }());
     }
diff --git a/src/mongo/s/catalog/sharding_catalog_client_test.cpp b/src/mongo/s/catalog/sharding_catalog_client_test.cpp
index 54528489f36..cd23a564d32 100644
--- a/src/mongo/s/catalog/sharding_catalog_client_test.cpp
+++ b/src/mongo/s/catalog/sharding_catalog_client_test.cpp
@@ -158,7 +158,8 @@ TEST_F(ShardingCatalogClientTest, GetDatabaseInvalidName) {
 TEST_F(ShardingCatalogClientTest, GetDatabaseExisting) {
     configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
 
-    DatabaseType expectedDb("bigdata", ShardId("shard0000"), true, DatabaseVersion(UUID::gen()));
+    DatabaseType expectedDb(
+        "bigdata", ShardId("shard0000"), true, DatabaseVersion(UUID::gen(), Timestamp()));
 
     const OpTime newOpTime(Timestamp(7, 6), 5);
 
@@ -205,7 +206,8 @@ TEST_F(ShardingCatalogClientTest, GetDatabaseStaleSecondaryRetrySuccess) {
     HostAndPort secondHost{"TestHost2"};
     configTargeter()->setFindHostReturnValue(firstHost);
 
-    DatabaseType expectedDb("bigdata", ShardId("shard0000"), true, DatabaseVersion(UUID::gen()));
+    DatabaseType expectedDb(
+        "bigdata", ShardId("shard0000"), true, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, &expectedDb] {
         return catalogClient()->getDatabase(
@@ -891,8 +893,10 @@ TEST_F(ShardingCatalogClientTest, GetCollectionsInvalidCollectionType) {
 TEST_F(ShardingCatalogClientTest, GetDatabasesForShardValid) {
     configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
 
-    DatabaseType dbt1("db1", ShardId("shard0000"), false, DatabaseVersion(UUID::gen()));
-    DatabaseType dbt2("db2", ShardId("shard0000"), false, DatabaseVersion(UUID::gen()));
+    DatabaseType dbt1(
+        "db1", ShardId("shard0000"), false, DatabaseVersion(UUID::gen(), Timestamp()));
+    DatabaseType dbt2(
+        "db2", ShardId("shard0000"), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this] {
         return assertGet(
@@ -934,7 +938,7 @@ TEST_F(ShardingCatalogClientTest, GetDatabasesForShardInvalidDoc) {
     });
 
     onFindCommand([](const RemoteCommandRequest& request) {
-        DatabaseType dbt1("db1", {"shard0000"}, false, DatabaseVersion(UUID::gen()));
+        DatabaseType dbt1("db1", {"shard0000"}, false, DatabaseVersion(UUID::gen(), Timestamp()));
         return vector<BSONObj>{
             dbt1.toBSON(),
             BSON(DatabaseType::name() << 0)  // DatabaseType::name() should be a string
@@ -1039,7 +1043,7 @@ TEST_F(ShardingCatalogClientTest, GetTagsForCollectionInvalidTag) {
 TEST_F(ShardingCatalogClientTest, UpdateDatabase) {
     configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
 
-    DatabaseType dbt("test", ShardId("shard0000"), true, DatabaseVersion(UUID::gen()));
+    DatabaseType dbt("test", ShardId("shard0000"), true, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, dbt] {
         auto status =
@@ -1086,7 +1090,8 @@ TEST_F(ShardingCatalogClientTest, UpdateConfigDocumentNonRetryableError) {
     HostAndPort host1("TestHost1");
     configTargeter()->setFindHostReturnValue(host1);
 
-    DatabaseType dbt("test", ShardId("shard0001"), false, DatabaseVersion(UUID::gen()));
+    DatabaseType dbt(
+        "test", ShardId("shard0001"), false, DatabaseVersion(UUID::gen(), Timestamp()));
 
     auto future = launchAsync([this, dbt] {
         auto status =
@@ -1287,7 +1292,8 @@ TEST_F(ShardingCatalogClientTest, RetryOnFindCommandNetworkErrorSucceedsAtMaxRet
     }
 
     onFindCommand([](const RemoteCommandRequest& request) {
-        DatabaseType dbType("TestDB", ShardId("TestShard"), true, DatabaseVersion(UUID::gen()));
+        DatabaseType dbType(
+            "TestDB", ShardId("TestShard"), true, DatabaseVersion(UUID::gen(), Timestamp()));
 
         return vector<BSONObj>{dbType.toBSON()};
     });
diff --git a/src/mongo/s/catalog/type_database_test.cpp b/src/mongo/s/catalog/type_database_test.cpp
index 8a9eb73dcda..fe126d6b390 100644
--- a/src/mongo/s/catalog/type_database_test.cpp
+++ b/src/mongo/s/catalog/type_database_test.cpp
@@ -47,10 +47,12 @@ TEST(DatabaseType, Empty) {
 
 TEST(DatabaseType, Basic) {
     UUID uuid = UUID::gen();
+    Timestamp timestamp = Timestamp();
     StatusWith<DatabaseType> status = DatabaseType::fromBSON(
         BSON(DatabaseType::name("mydb")
              << DatabaseType::primary("shard") << DatabaseType::sharded(true)
-             << DatabaseType::version(BSON("uuid" << uuid << "lastMod" << 0))));
+             << DatabaseType::version(
+                    BSON("uuid" << uuid << "lastMod" << 0 << "timestamp" << timestamp))));
     ASSERT_TRUE(status.isOK());
 
     DatabaseType db = status.getValue();
diff --git a/src/mongo/s/catalog_cache_refresh_test.cpp b/src/mongo/s/catalog_cache_refresh_test.cpp
index 6a527696088..9560317bc54 100644
--- a/src/mongo/s/catalog_cache_refresh_test.cpp
+++ b/src/mongo/s/catalog_cache_refresh_test.cpp
@@ -59,7 +59,8 @@ protected:
 
     void expectGetDatabase() {
         expectFindSendBSONObjVector(kConfigHostAndPort, [&]() {
-            DatabaseType db(kNss.db().toString(), {"0"}, true, DatabaseVersion(UUID::gen()));
+            DatabaseType db(
+                kNss.db().toString(), {"0"}, true, DatabaseVersion(UUID::gen(), Timestamp()));
             return std::vector<BSONObj>{db.toBSON()};
         }());
     }
diff --git a/src/mongo/s/catalog_cache_test.cpp b/src/mongo/s/catalog_cache_test.cpp
index 0d6827577ff..5e5d41c7df8 100644
--- a/src/mongo/s/catalog_cache_test.cpp
+++ b/src/mongo/s/catalog_cache_test.cpp
@@ -181,7 +181,7 @@ protected:
 
 TEST_F(CatalogCacheTest, GetDatabase) {
     const auto dbName = "testDB";
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     _catalogCacheLoader->setDatabaseRefreshReturnValue(
         DatabaseType(dbName, kShards[0], true, dbVersion));
 
@@ -197,7 +197,7 @@ TEST_F(CatalogCacheTest, GetDatabase) {
 
 TEST_F(CatalogCacheTest, GetCachedDatabase) {
     const auto dbName = "testDB";
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     loadDatabases({DatabaseType(dbName, kShards[0], true, dbVersion)});
 
     const auto swDatabase = _catalogCache->getDatabase(operationContext(), dbName);
@@ -212,7 +212,7 @@ TEST_F(CatalogCacheTest, GetCachedDatabase) {
 
 TEST_F(CatalogCacheTest, InvalidateSingleDbOnShardRemoval) {
     const auto dbName = "testDB";
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     loadDatabases({DatabaseType(dbName, kShards[0], true, dbVersion)});
 
     _catalogCache->invalidateEntriesThatReferenceShard(kShards[0]);
@@ -227,7 +227,7 @@ TEST_F(CatalogCacheTest, InvalidateSingleDbOnShardRemoval) {
 
 TEST_F(CatalogCacheTest, OnStaleDatabaseVersionNoVersion) {
     // onStaleDatabaseVesrsion must invalidate the database entry if invoked with no version
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     loadDatabases({DatabaseType(kNss.db().toString(), kShards[0], true, dbVersion)});
 
     _catalogCache->onStaleDatabaseVersion(kNss.db(), boost::none);
@@ -237,7 +237,7 @@ TEST_F(CatalogCacheTest, OnStaleDatabaseVersionNoVersion) {
 }
 
 TEST_F(CatalogCacheTest, OnStaleShardVersionWithSameVersion) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto cachedCollVersion = ChunkVersion(1, 0, OID::gen(), boost::none /* timestamp */);
 
     loadDatabases({DatabaseType(kNss.db().toString(), kShards[0], true, dbVersion)});
@@ -248,7 +248,7 @@ TEST_F(CatalogCacheTest, OnStaleShardVersionWithSameVersion) {
 }
 
 TEST_F(CatalogCacheTest, OnStaleShardVersionWithNoVersion) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto cachedCollVersion = ChunkVersion(1, 0, OID::gen(), boost::none /* timestamp */);
 
     loadDatabases({DatabaseType(kNss.db().toString(), kShards[0], true, dbVersion)});
@@ -261,7 +261,7 @@ TEST_F(CatalogCacheTest, OnStaleShardVersionWithNoVersion) {
 }
 
 TEST_F(CatalogCacheTest, OnStaleShardVersionWithGraterVersion) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto cachedCollVersion = ChunkVersion(1, 0, OID::gen(), boost::none /* timestamp */);
     const auto wantedCollVersion =
         ChunkVersion(2, 0, cachedCollVersion.epoch(), cachedCollVersion.getTimestamp());
@@ -278,7 +278,7 @@ TEST_F(CatalogCacheTest, OnStaleShardVersionWithGraterVersion) {
 TEST_F(CatalogCacheTest, GetDatabaseWithMetadataFormatChange) {
     const auto dbName = "testDB";
     const auto uuid = UUID::gen();
-    const DatabaseVersion versionWithoutTimestamp(uuid);
+    const DatabaseVersion versionWithoutTimestamp(uuid, Timestamp());
     const DatabaseVersion versionWithTimestamp(uuid, Timestamp(42));
 
     auto getDatabaseWithRefreshAndCheckResults = [&](const DatabaseVersion& version) {
@@ -303,7 +303,7 @@ TEST_F(CatalogCacheTest, GetDatabaseWithMetadataFormatChange) {
 }
 
 TEST_F(CatalogCacheTest, GetCollectionWithMetadataFormatChange) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto collVersionWithoutTimestamp = ChunkVersion(1, 0, epoch, boost::none /* timestamp */);
     const auto collVersionWithTimestamp = ChunkVersion(1, 0, epoch, Timestamp(42));
@@ -342,7 +342,7 @@ TEST_F(CatalogCacheTest, GetCollectionWithMetadataFormatChange) {
 
 TEST_F(CatalogCacheTest,
        GetCollectionWithRefreshDuringUpgradeWithMetadataFormatChangeChunksDontMatchCollection) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto timestamp = Timestamp(42);
 
@@ -372,7 +372,7 @@ TEST_F(CatalogCacheTest,
 
 TEST_F(CatalogCacheTest,
        GetCollectionWithRefreshDuringUpgradeWithMetadataFormatChangeSomeChunksMatchCollection) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto timestamp = Timestamp(42);
 
@@ -409,7 +409,7 @@ TEST_F(CatalogCacheTest,
 }
 
 TEST_F(CatalogCacheTest, GetCollectionWithRefreshDuringDowngradeWithMetadataFormatChange) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto timestamp = Timestamp(42);
 
@@ -438,7 +438,7 @@ TEST_F(CatalogCacheTest, GetCollectionWithRefreshDuringDowngradeWithMetadataForm
 }
 
 TEST_F(CatalogCacheTest, TimeseriesFieldsAreProperlyPropagatedOnCC) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto version = ChunkVersion(1, 0, epoch, Timestamp(42));
 
@@ -461,7 +461,7 @@ TEST_F(CatalogCacheTest, TimeseriesFieldsAreProperlyPropagatedOnCC) {
 }
 
 TEST_F(CatalogCacheTest, LookupCollectionWithInvalidOptions) {
-    const auto dbVersion = DatabaseVersion(UUID::gen());
+    const auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
     const auto epoch = OID::gen();
     const auto version = ChunkVersion(1, 0, epoch, Timestamp(42));
 
diff --git a/src/mongo/s/catalog_cache_test_fixture.cpp b/src/mongo/s/catalog_cache_test_fixture.cpp
index 30ac640025c..975c8804914 100644
--- a/src/mongo/s/catalog_cache_test_fixture.cpp
+++ b/src/mongo/s/catalog_cache_test_fixture.cpp
@@ -133,7 +133,8 @@ ChunkManager CatalogCacheTestFixture::makeChunkManager(
     ChunkVersion version(1, 0, OID::gen(), boost::none /* timestamp */);
 
     const BSONObj databaseBSON = [&]() {
-        DatabaseType db(nss.db().toString(), {"0"}, true, DatabaseVersion(UUID::gen()));
+        DatabaseType db(
+            nss.db().toString(), {"0"}, true, DatabaseVersion(UUID::gen(), Timestamp()));
         return db.toBSON();
     }();
 
@@ -194,7 +195,8 @@ ChunkManager CatalogCacheTestFixture::makeChunkManager(
 
 void CatalogCacheTestFixture::expectGetDatabase(NamespaceString nss, std::string shardId) {
     expectFindSendBSONObjVector(kConfigHostAndPort, [&]() {
-        DatabaseType db(nss.db().toString(), {shardId}, true, DatabaseVersion(UUID::gen()));
+        DatabaseType db(
+            nss.db().toString(), {shardId}, true, DatabaseVersion(UUID::gen(), Timestamp()));
         return std::vector<BSONObj>{db.toBSON()};
     }());
 }
diff --git a/src/mongo/s/chunk_manager_query_test.cpp b/src/mongo/s/chunk_manager_query_test.cpp
index 47b325d5414..5d9832ae690 100644
--- a/src/mongo/s/chunk_manager_query_test.cpp
+++ b/src/mongo/s/chunk_manager_query_test.cpp
@@ -533,7 +533,7 @@ TEST_F(ChunkManagerQueryTest, SnapshotQueryWithMoreShardsThanLatestMetadata) {
                        ChunkHistory(Timestamp(1, 0), ShardId("1"))});
 
     ChunkManager chunkManager(ShardId("0"),
-                              DatabaseVersion(UUID::gen()),
+                              DatabaseVersion(UUID::gen(), Timestamp()),
                               makeStandaloneRoutingTableHistory(oldRoutingTable.makeUpdated(
                                   boost::none, boost::none, true, {chunk1})),
                               Timestamp(5, 0));
diff --git a/src/mongo/s/chunk_manager_refresh_bm.cpp b/src/mongo/s/chunk_manager_refresh_bm.cpp
index dd1012548dc..a8c7b626331 100644
--- a/src/mongo/s/chunk_manager_refresh_bm.cpp
+++ b/src/mongo/s/chunk_manager_refresh_bm.cpp
@@ -92,7 +92,7 @@ CollectionMetadata makeChunkManagerWithShardSelector(int nShards,
                                            true,
                                            chunks);
     return CollectionMetadata(ChunkManager(ShardId("Shard0"),
-                                           DatabaseVersion(UUID::gen()),
+                                           DatabaseVersion(UUID::gen(), Timestamp()),
                                            makeStandaloneRoutingTableHistory(std::move(rt)),
                                            boost::none),
                               ShardId("shard0"));
@@ -123,7 +123,7 @@ MONGO_COMPILER_NOINLINE auto runIncrementalUpdate(const CollectionMetadata& cm,
     auto rt = cm.getChunkManager()->getRoutingTableHistory_ForTest().makeUpdated(
         boost::none, boost::none, true, newChunks);
     return CollectionMetadata(ChunkManager(ShardId("shard0"),
-                                           DatabaseVersion(UUID::gen()),
+                                           DatabaseVersion(UUID::gen(), Timestamp()),
                                            makeStandaloneRoutingTableHistory(std::move(rt)),
                                            boost::none),
                               ShardId("shard0"));
@@ -184,7 +184,7 @@ auto BM_FullBuildOfChunkManager(benchmark::State& state, ShardSelectorFn selectS
                                                chunks);
         benchmark::DoNotOptimize(
             CollectionMetadata(ChunkManager(ShardId("shard0"),
-                                            DatabaseVersion(UUID::gen()),
+                                            DatabaseVersion(UUID::gen(), Timestamp()),
                                             makeStandaloneRoutingTableHistory(std::move(rt)),
                                             boost::none),
                                ShardId("shard0")));
diff --git a/src/mongo/s/comparable_database_version_test.cpp b/src/mongo/s/comparable_database_version_test.cpp
index cbf2d9b6869..2e2ce305ed9 100644
--- a/src/mongo/s/comparable_database_version_test.cpp
+++ b/src/mongo/s/comparable_database_version_test.cpp
@@ -42,7 +42,6 @@ TEST(ComparableDatabaseVersionTest, VersionsEqual) {
         ASSERT(version == version);
     };
 
-    versionsEqual(DatabaseVersion(UUID::gen()));
     versionsEqual(DatabaseVersion(UUID::gen(), Timestamp(1)));
 }
 
@@ -53,20 +52,9 @@ TEST(ComparableDatabaseVersionTest, VersionsEqualAfterCopy) {
         ASSERT(version1 == version2);
     };
 
-    versionsEqualAfterCopy(DatabaseVersion(UUID::gen()));
     versionsEqualAfterCopy(DatabaseVersion(UUID::gen(), Timestamp(1)));
 }
 
-TEST(ComparableDatabaseVersionTest, CompareVersionDifferentUuids) {
-    const auto version1 =
-        ComparableDatabaseVersion::makeComparableDatabaseVersion(DatabaseVersion(UUID::gen()));
-    const auto version2 =
-        ComparableDatabaseVersion::makeComparableDatabaseVersion(DatabaseVersion(UUID::gen()));
-    ASSERT(version2 != version1);
-    ASSERT(version2 > version1);
-    ASSERT_FALSE(version2 < version1);
-}
-
 TEST(ComparableDatabaseVersionTest, CompareVersionDifferentTimestamps) {
     const auto version1 = ComparableDatabaseVersion::makeComparableDatabaseVersion(
         DatabaseVersion(UUID::gen(), Timestamp(3)));
@@ -77,57 +65,6 @@ TEST(ComparableDatabaseVersionTest, CompareVersionDifferentTimestamps) {
     ASSERT_FALSE(version2 > version1);
 }
 
-TEST(ComparableDatabaseVersionTest, CompareEpochBasedVersionAgainstEpochAndTimestampBasedVersion) {
-    {
-        auto equalVersions = [](const DatabaseVersion& v1, const DatabaseVersion& v2) {
-            const auto version1 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v1);
-            const auto version2 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v2);
-            ASSERT(version1 == version2);
-            ASSERT_FALSE(version1 < version2);
-            ASSERT_FALSE(version1 > version2);
-        };
-
-        const auto epoch = UUID::gen();
-        const DatabaseVersion v1(epoch);
-        const DatabaseVersion v2(epoch, Timestamp(1));
-        equalVersions(v1, v2);
-        equalVersions(v2, v1);
-    }
-
-    {
-        auto diffVersionsMoreRecentByLastMod = [](const DatabaseVersion& v1,
-                                                  const DatabaseVersion& v2) {
-            const auto version1 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v1);
-            const auto version2 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v2);
-            ASSERT(version1 != version2);
-            ASSERT(version1 > version2);
-            ASSERT_FALSE(version1 < version2);
-        };
-
-        const auto epoch = UUID::gen();
-        const DatabaseVersion v1(epoch);
-        const DatabaseVersion v2(epoch, Timestamp(1));
-        diffVersionsMoreRecentByLastMod(v1.makeUpdated(), v2);
-        diffVersionsMoreRecentByLastMod(v2.makeUpdated(), v1);
-    }
-
-    {
-        auto diffVersionsMoreRecentByDisambigSeqNum = [](const DatabaseVersion& v1,
-                                                         const DatabaseVersion& v2) {
-            const auto version1 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v1);
-            const auto version2 = ComparableDatabaseVersion::makeComparableDatabaseVersion(v2);
-            ASSERT(version1 != version2);
-            ASSERT(version1 < version2);
-            ASSERT_FALSE(version1 > version2);
-        };
-
-        const DatabaseVersion v1(UUID::gen());
-        const DatabaseVersion v2(UUID::gen(), Timestamp(1));
-        diffVersionsMoreRecentByDisambigSeqNum(v1, v2);
-        diffVersionsMoreRecentByDisambigSeqNum(v2, v1);
-    }
-}
-
 TEST(ComparableDatabaseVersionTest, VersionGreaterSameUuidOrTimestamp) {
     auto versionGreaterSameUuidOrTimestamp = [](const DatabaseVersion& v1) {
         const DatabaseVersion v2 = v1.makeUpdated();
@@ -138,8 +75,7 @@ TEST(ComparableDatabaseVersionTest, VersionGreaterSameUuidOrTimestamp) {
         ASSERT_FALSE(version2 < version1);
     };
 
-    versionGreaterSameUuidOrTimestamp(DatabaseVersion(UUID::gen()));
-    versionGreaterSameUuidOrTimestamp(DatabaseVersion(UUID::gen(), Timestamp(1)));
+    versionGreaterSameUuidOrTimestamp(DatabaseVersion(UUID::gen(), Timestamp(0)));
 }
 
 TEST(ComparableDatabaseVersionTest, VersionLessSameUuidOrTimestamp) {
@@ -152,7 +88,6 @@ TEST(ComparableDatabaseVersionTest, VersionLessSameUuidOrTimestamp) {
         ASSERT_FALSE(version1 > version2);
     };
 
-    versionLessSameUuidOrTimestamp(DatabaseVersion(UUID::gen()));
     versionLessSameUuidOrTimestamp(DatabaseVersion(UUID::gen(), Timestamp(1)));
 }
 
@@ -173,8 +108,7 @@ TEST(ComparableDatabaseVersionTest, DefaultConstructedVersionIsAlwaysLess) {
         ASSERT_FALSE(defaultVersion > version1);
     };
 
-    defaultConstructedVersionIsAlwaysLess(DatabaseVersion(UUID::gen()));
-    defaultConstructedVersionIsAlwaysLess(DatabaseVersion(UUID::gen(), Timestamp(1)));
+    defaultConstructedVersionIsAlwaysLess(DatabaseVersion(UUID::gen(), Timestamp()));
 }
 
 TEST(ComparableDatabaseVersionTest, CompareForcedRefreshVersionVersusValidDatabaseVersion) {
@@ -199,9 +133,8 @@ TEST(ComparableDatabaseVersionTest, CompareForcedRefreshVersionVersusValidDataba
         ASSERT(defaultVersionAfterForce < forcedRefreshVersion);
     };
 
-    compareForcedRefreshVersionVersusValidDatabaseVersion(DatabaseVersion(UUID::gen()));
     compareForcedRefreshVersionVersusValidDatabaseVersion(
-        DatabaseVersion(UUID::gen(), Timestamp(1)));
+        DatabaseVersion(UUID::gen(), Timestamp()));
 }
 
 TEST(ComparableDatabaseVersionTest, CompareTwoForcedRefreshVersions) {
diff --git a/src/mongo/s/database_version.cpp b/src/mongo/s/database_version.cpp
index 7ca5de2f01b..3a0af40956a 100644
--- a/src/mongo/s/database_version.cpp
+++ b/src/mongo/s/database_version.cpp
@@ -37,9 +37,8 @@ AtomicWord<uint64_t> ComparableDatabaseVersion::_uuidDisambiguatingSequenceNumSo
 AtomicWord<uint64_t> ComparableDatabaseVersion::_forcedRefreshSequenceNumSource{1ULL};
 
 DatabaseVersion DatabaseVersion::makeFixed() {
-    DatabaseVersion dbVersion;
+    DatabaseVersion dbVersion(UUID::gen(), Timestamp());
     dbVersion.setLastMod(0);
-    dbVersion.setUuid(UUID::gen());
     return dbVersion;
 }
 DatabaseVersion DatabaseVersion::makeUpdated() const {
@@ -104,23 +103,17 @@ bool ComparableDatabaseVersion::operator<(const ComparableDatabaseVersion& other
         return false;  // Only default constructed values have _forcedRefreshSequenceNum == 0 and
                        // they are always equal
 
-    // 1. If both versions are valid and have timestamps
-    //    1.1. if their timestamps are the same -> rely on lastMod to define the order
-    //    1.2. Otherwise  -> rely on the timestamps values to define order
-    // 2. If both versions are valid and have the same uuid -> rely on lastMod to define the order
-    // 3. Any other scenario -> rely on disambiguating sequence number
+    // 1. If both versions are valid
+    // 1.1. If both timestamps are the same -> rely on lastMod to define the order
+    // 1.2. Otherwise  -> rely on the timestamps' values to define order
+    // 2. Any other scenario -> rely on disambiguating sequence number
     if (_dbVersion && other._dbVersion) {
         const auto timestamp = _dbVersion->getTimestamp();
         const auto otherTimestamp = other._dbVersion->getTimestamp();
-        if (timestamp && otherTimestamp) {
-            if (*timestamp == *otherTimestamp)
-                return _dbVersion->getLastMod() < other._dbVersion->getLastMod();
-            else
-                return *timestamp < *otherTimestamp;
-
-        } else if (_dbVersion->getUuid() == other._dbVersion->getUuid()) {
+        if (timestamp == otherTimestamp)
             return _dbVersion->getLastMod() < other._dbVersion->getLastMod();
-        }
+        else
+            return timestamp < otherTimestamp;
     }
 
     return _uuidDisambiguatingSequenceNum < other._uuidDisambiguatingSequenceNum;
diff --git a/src/mongo/s/database_version.h b/src/mongo/s/database_version.h
index 2bfad7d883d..87ecdb6b371 100644
--- a/src/mongo/s/database_version.h
+++ b/src/mongo/s/database_version.h
@@ -47,8 +47,6 @@ class DatabaseVersion : public DatabaseVersionBase {
 public:
     using DatabaseVersionBase::getTimestamp;
 
-    DatabaseVersion() = default;
-
     explicit DatabaseVersion(const BSONObj& obj) {
         DatabaseVersionBase::parseProtected(IDLParserErrorContext("DatabaseVersion"), obj);
     }
@@ -56,18 +54,11 @@ public:
     explicit DatabaseVersion(const DatabaseVersionBase& dbv) : DatabaseVersionBase(dbv) {}
 
     /**
-     * Constructor of a DatabaseVersion based on epochs
-     */
-    explicit DatabaseVersion(mongo::UUID uuid)
-        : DatabaseVersion(uuid, boost::none /* timestamp */) {}
-
-    /**
      * Constructor of a DatabaseVersion based on epochs and timestamps
      */
-    DatabaseVersion(mongo::UUID uuid, boost::optional<mongo::Timestamp> timestamp)
-        : DatabaseVersionBase(1 /* lastMod */) {
+    DatabaseVersion(mongo::UUID uuid, mongo::Timestamp timestamp)
+        : DatabaseVersionBase(timestamp, 1 /* lastMod */) {
         setUuid(uuid);
-        setTimestamp(timestamp);
     }
 
     // Returns a new hardcoded DatabaseVersion value, which is used to distinguish databases that do
diff --git a/src/mongo/s/database_version.idl b/src/mongo/s/database_version.idl
index 557c1d1d6b9..9b073f5a34e 100644
--- a/src/mongo/s/database_version.idl
+++ b/src/mongo/s/database_version.idl
@@ -48,10 +48,7 @@ structs:
                 optional: true
             timestamp:
                 type: timestamp
-                description: "Uniquely identifies to distinguish different incarnations of this database
-                              It is optional for parsing purposes, because in versions of MongoDB
-                              prior to 5.0, this value wasn't being written."
-                optional: true
+                description: "Uniquely identifies to distinguish different incarnations of this database."
             lastMod:
                 type: int
                 description: "an integer which is bumped whenever the database's primary shard changes"
diff --git a/src/mongo/s/write_ops/batch_write_exec_test.cpp b/src/mongo/s/write_ops/batch_write_exec_test.cpp
index ca3bf151737..6f8f077859d 100644
--- a/src/mongo/s/write_ops/batch_write_exec_test.cpp
+++ b/src/mongo/s/write_ops/batch_write_exec_test.cpp
@@ -140,7 +140,7 @@ BSONObj expectInsertsReturnStaleDbVersionErrorsBase(const NamespaceString& nss,
         errorBuilder.append("index", i);
         errorBuilder.append("code", int(ErrorCodes::StaleDbVersion));
 
-        auto dbVersion = DatabaseVersion(UUID::gen());
+        auto dbVersion = DatabaseVersion(UUID::gen(), Timestamp());
         errorBuilder.append("db", nss.db());
         errorBuilder.append("vReceived", dbVersion.toBSON());
         errorBuilder.append("vWanted", dbVersion.makeUpdated().toBSON());