SERVER-52802 Remove kDropping from the ReshardingCoordinator

6 files changed, 39 insertions, 51 deletions

diff --git a/src/mongo/db/s/collection_metadata.cpp b/src/mongo/db/s/collection_metadata.cpp
index a8598ce826b..d72b013b9ac 100644
--- a/src/mongo/db/s/collection_metadata.cpp
+++ b/src/mongo/db/s/collection_metadata.cpp
@@ -70,7 +70,6 @@ boost::optional<ShardKeyPattern> CollectionMetadata::getReshardingKeyIfShouldFor
         case CoordinatorStateEnum::kMirroring:
         case CoordinatorStateEnum::kCommitted:
         case CoordinatorStateEnum::kRenaming:
-        case CoordinatorStateEnum::kDropping:
         case CoordinatorStateEnum::kDone:
         case CoordinatorStateEnum::kError:
             return boost::none;
@@ -109,7 +108,6 @@ bool CollectionMetadata::writesShouldRunInDistributedTransaction(const OID& orig
             return true;
         case CoordinatorStateEnum::kRenaming:
             break;
-        case CoordinatorStateEnum::kDropping:
         case CoordinatorStateEnum::kDone:
         case CoordinatorStateEnum::kError:
             return false;
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_observer.h b/src/mongo/db/s/resharding/resharding_coordinator_observer.h
index b3e1e4acf35..27a64fa53be 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_observer.h
+++ b/src/mongo/db/s/resharding/resharding_coordinator_observer.h
@@ -92,18 +92,18 @@ public:
     SharedSemiFuture<ReshardingCoordinatorDocument> awaitAllRecipientsInStrictConsistency();
 
     /**
-     * Fulfills the '_allDonorsDroppedOriginalCollection' promise when the last donor writes that it
-     * is in 'done' state.
-     */
-    SharedSemiFuture<ReshardingCoordinatorDocument> awaitAllDonorsDroppedOriginalCollection();
-
-    /**
      * Fulfills the '_allRecipientsRenamedCollection' promise when the last recipient writes
      * that it is in 'done' state.
      */
     SharedSemiFuture<ReshardingCoordinatorDocument> awaitAllRecipientsRenamedCollection();
 
     /**
+     * Fulfills the '_allDonorsDroppedOriginalCollection' promise when the last donor writes that it
+     * is in 'done' state.
+     */
+    SharedSemiFuture<ReshardingCoordinatorDocument> awaitAllDonorsDroppedOriginalCollection();
+
+    /**
      * Sets errors on any promises that have not yet been fulfilled.
      */
     void interrupt(Status status);
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
index b90af097d0b..2e9b66818b6 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
@@ -44,6 +44,7 @@
 #include "mongo/s/grid.h"
 #include "mongo/s/shard_id.h"
 #include "mongo/s/write_ops/batched_command_response.h"
+#include "mongo/util/future_util.h"
 #include "mongo/util/string_map.h"
 #include "mongo/util/uuid.h"
 
@@ -398,17 +399,16 @@ std::vector<ShardId> extractShardIds(const std::vector<T>& participantShardEntri
 /**
  * Maps which participants are to be notified when the coordinator transitions into a given state.
  */
-enum class ParticipantsToNofityEnum { kDonors, kRecipientsTempNss, kRecipientsOrigNss, kNone };
+enum class ParticipantsToNofityEnum { kDonors, kRecipients, kAllParticipantsPostCommit, kNone };
 stdx::unordered_map<CoordinatorStateEnum, ParticipantsToNofityEnum> notifyForStateTransition{
     {CoordinatorStateEnum::kUnused, ParticipantsToNofityEnum::kNone},
     {CoordinatorStateEnum::kInitializing, ParticipantsToNofityEnum::kNone},
     {CoordinatorStateEnum::kPreparingToDonate, ParticipantsToNofityEnum::kDonors},
-    {CoordinatorStateEnum::kCloning, ParticipantsToNofityEnum::kRecipientsTempNss},
+    {CoordinatorStateEnum::kCloning, ParticipantsToNofityEnum::kRecipients},
     {CoordinatorStateEnum::kApplying, ParticipantsToNofityEnum::kDonors},
     {CoordinatorStateEnum::kMirroring, ParticipantsToNofityEnum::kDonors},
     {CoordinatorStateEnum::kCommitted, ParticipantsToNofityEnum::kNone},
-    {CoordinatorStateEnum::kRenaming, ParticipantsToNofityEnum::kRecipientsOrigNss},
-    {CoordinatorStateEnum::kDropping, ParticipantsToNofityEnum::kDonors},
+    {CoordinatorStateEnum::kRenaming, ParticipantsToNofityEnum::kAllParticipantsPostCommit},
     {CoordinatorStateEnum::kDone, ParticipantsToNofityEnum::kNone},
     {CoordinatorStateEnum::kError, ParticipantsToNofityEnum::kNone},
 };
@@ -462,7 +462,7 @@ void bumpShardVersionsThenExecuteStateTransitionAndMetadataChangesInTxn(
             updatedCoordinatorDoc.getNss(),
             extractShardIds(updatedCoordinatorDoc.getDonorShards()),
             std::move(changeMetadataFunc));
-    } else if (participantsToNotify == ParticipantsToNofityEnum::kRecipientsTempNss) {
+    } else if (participantsToNotify == ParticipantsToNofityEnum::kRecipients) {
         // Bump the recipient shard versions for the temporary resharding namespace along with
         // updating the metadata.
         ShardingCatalogManager::get(opCtx)->bumpCollShardVersionsAndChangeMetadataInTxn(
@@ -470,9 +470,10 @@ void bumpShardVersionsThenExecuteStateTransitionAndMetadataChangesInTxn(
             updatedCoordinatorDoc.getTempReshardingNss(),
             extractShardIds(updatedCoordinatorDoc.getRecipientShards()),
             std::move(changeMetadataFunc));
-    } else if (participantsToNotify == ParticipantsToNofityEnum::kRecipientsOrigNss) {
+    } else if (participantsToNotify == ParticipantsToNofityEnum::kAllParticipantsPostCommit) {
         // Bump the recipient shard versions for the original resharding namespace along with
-        // updating the metadata.
+        // updating the metadata. Only the recipient shards will have chunks for the namespace
+        // after commit, bumping chunk versions on the donor shards would not apply.
         ShardingCatalogManager::get(opCtx)->bumpCollShardVersionsAndChangeMetadataInTxn(
             opCtx,
             updatedCoordinatorDoc.getNss(),
@@ -678,11 +679,10 @@ SemiFuture<void> ReshardingCoordinatorService::ReshardingCoordinator::run(
                                                         _coordinatorDoc);
             return;
         })
-        .then([this, executor] { _tellAllRecipientsToRefresh(executor); })
-        .then([this, executor] { return _awaitAllRecipientsRenamedCollection(executor); })
-        .then([this, executor] { _tellAllDonorsToRefresh(executor); })
-        .then([this, executor] { return _awaitAllDonorsDroppedOriginalCollection(executor); })
         .then([this, executor] { _tellAllParticipantsToRefresh(executor); })
+        .then([this, executor] {
+            return _awaitAllParticipantShardsRenamedOrDroppedOriginalCollection(executor);
+        })
         .onError([this, executor](Status status) {
             stdx::lock_guard<Latch> lg(_mutex);
             if (_completionPromise.getFuture().isReady()) {
@@ -859,33 +859,26 @@ Future<void> ReshardingCoordinatorService::ReshardingCoordinator::_commit(
     return Status::OK();
 };
 
-ExecutorFuture<void>
-ReshardingCoordinatorService::ReshardingCoordinator::_awaitAllRecipientsRenamedCollection(
-    const std::shared_ptr<executor::ScopedTaskExecutor>& executor) {
+ExecutorFuture<void> ReshardingCoordinatorService::ReshardingCoordinator::
+    _awaitAllParticipantShardsRenamedOrDroppedOriginalCollection(
+        const std::shared_ptr<executor::ScopedTaskExecutor>& executor) {
     if (_coordinatorDoc.getState() > CoordinatorStateEnum::kRenaming) {
         return ExecutorFuture<void>(**executor, Status::OK());
     }
 
-    return _reshardingCoordinatorObserver->awaitAllRecipientsRenamedCollection()
-        .thenRunOn(**executor)
-        .then([this](ReshardingCoordinatorDocument coordinatorDocChangedOnDisk) {
-            _updateCoordinatorDocStateAndCatalogEntries(CoordinatorStateEnum::kDropping,
-                                                        coordinatorDocChangedOnDisk);
-        });
-}
-
-ExecutorFuture<void>
-ReshardingCoordinatorService::ReshardingCoordinator::_awaitAllDonorsDroppedOriginalCollection(
-    const std::shared_ptr<executor::ScopedTaskExecutor>& executor) {
-    if (_coordinatorDoc.getState() > CoordinatorStateEnum::kDropping) {
-        return ExecutorFuture<void>(**executor, Status::OK());
-    }
+    std::vector<ExecutorFuture<ReshardingCoordinatorDocument>> futures;
+    futures.emplace_back(
+        _reshardingCoordinatorObserver->awaitAllRecipientsRenamedCollection().thenRunOn(
+            **executor));
+    futures.emplace_back(
+        _reshardingCoordinatorObserver->awaitAllDonorsDroppedOriginalCollection().thenRunOn(
+            **executor));
 
-    return _reshardingCoordinatorObserver->awaitAllDonorsDroppedOriginalCollection()
+    return whenAllSucceed(std::move(futures))
         .thenRunOn(**executor)
-        .then([this](ReshardingCoordinatorDocument coordinatorDocChangedOnDisk) {
+        .then([this, executor](const auto& coordinatorDocsChangedOnDisk) {
             _updateCoordinatorDocStateAndCatalogEntries(CoordinatorStateEnum::kDone,
-                                                        coordinatorDocChangedOnDisk);
+                                                        coordinatorDocsChangedOnDisk[1]);
         });
 }
 
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.h b/src/mongo/db/s/resharding/resharding_coordinator_service.h
index 26cca998bea..833a9f4450d 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.h
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.h
@@ -182,17 +182,15 @@ private:
     Future<void> _commit(const ReshardingCoordinatorDocument& updatedDoc);
 
     /**
-     * Waits on _reshardingCoordinatorObserver to notify that all recipients have renamed the
-     * temporary collection to the original collection namespace. Transitions to 'kDropping'.
-     */
-    ExecutorFuture<void> _awaitAllRecipientsRenamedCollection(
-        const std::shared_ptr<executor::ScopedTaskExecutor>& executor);
-
-    /**
-     * Waits on _reshardingCoordinatorObserver to notify that all donors have dropped the
-     * original collection. Transitions to 'kDone'.
+     * Waits on _reshardingCoordinatorObserver to notify that:
+     * 1. All recipient shards have renamed the temporary collection to the original collection
+     *    namespace, and
+     * 2. All donor shards that were not also recipient shards have dropped the original
+     *    collection.
+     *
+     * Transitions to 'kDone'.
      */
-    ExecutorFuture<void> _awaitAllDonorsDroppedOriginalCollection(
+    ExecutorFuture<void> _awaitAllParticipantShardsRenamedOrDroppedOriginalCollection(
         const std::shared_ptr<executor::ScopedTaskExecutor>& executor);
 
     /**
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_test.cpp b/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
index 4810d2710ef..3c455384ceb 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
@@ -681,7 +681,7 @@ TEST_F(ReshardingCoordinatorPersistenceTest, PersistTransitionToErrorSucceeds) {
 
 TEST_F(ReshardingCoordinatorPersistenceTest, PersistTransitionToDoneSucceeds) {
     auto coordinatorDoc =
-        insertStateAndCatalogEntries(CoordinatorStateEnum::kDropping, _finalEpoch);
+        insertStateAndCatalogEntries(CoordinatorStateEnum::kRenaming, _finalEpoch);
 
     // Persist the updates on disk
     auto expectedCoordinatorDoc = coordinatorDoc;
diff --git a/src/mongo/s/resharding/common_types.idl b/src/mongo/s/resharding/common_types.idl
index 6928129a6ff..41368c2c60a 100644
--- a/src/mongo/s/resharding/common_types.idl
+++ b/src/mongo/s/resharding/common_types.idl
@@ -49,7 +49,6 @@ enums:
             kMirroring: "mirroring"
             kCommitted: "committed"
             kRenaming: "renaming"
-            kDropping: "dropping"
             kDone: "done"
             kError: "error"