SERVER-25673 Remove redundant ChunkManager access in MigrationManager

4 files changed, 9 insertions, 42 deletions

diff --git a/src/mongo/db/s/active_migrations_registry_test.cpp b/src/mongo/db/s/active_migrations_registry_test.cpp
index c5eb63f71a3..7907434e0d0 100644
--- a/src/mongo/db/s/active_migrations_registry_test.cpp
+++ b/src/mongo/db/s/active_migrations_registry_test.cpp
@@ -65,19 +65,17 @@ protected:
 };
 
 MoveChunkRequest createMoveChunkRequest(const NamespaceString& nss) {
-    const ChunkVersion collectionVersion(2, 3, OID::gen());
     const ChunkVersion chunkVersion(1, 2, OID::gen());
 
     BSONObjBuilder builder;
     MoveChunkRequest::appendAsCommand(
         &builder,
         nss,
-        collectionVersion,
+        chunkVersion,
         assertGet(ConnectionString::parse("TestConfigRS/CS1:12345,CS2:12345,CS3:12345")),
         ShardId("shard0001"),
         ShardId("shard0002"),
         ChunkRange(BSON("Key" << -100), BSON("Key" << 100)),
-        chunkVersion,
         1024,
         MigrationSecondaryThrottleOptions::create(MigrationSecondaryThrottleOptions::kOff),
         true);
diff --git a/src/mongo/db/s/balancer/migration_manager.cpp b/src/mongo/db/s/balancer/migration_manager.cpp
index 6bccabf7326..02c9fece761 100644
--- a/src/mongo/db/s/balancer/migration_manager.cpp
+++ b/src/mongo/db/s/balancer/migration_manager.cpp
@@ -454,29 +454,6 @@ shared_ptr<Notification<RemoteCommandResponse>> MigrationManager::_schedule(
         }
     }
 
-
-    // Sanity checks that the chunk being migrated is actually valid. These will be repeated at the
-    // shard as well, but doing them here saves an extra network call, which might otherwise fail.
-    auto statusWithScopedChunkManager = ScopedChunkManager::refreshAndGet(txn, nss);
-    if (!statusWithScopedChunkManager.isOK()) {
-        return std::make_shared<Notification<RemoteCommandResponse>>(
-            std::move(statusWithScopedChunkManager.getStatus()));
-    }
-
-    ChunkManager* const chunkManager = statusWithScopedChunkManager.getValue().cm();
-
-    auto chunk = chunkManager->findIntersectingChunkWithSimpleCollation(txn, migrateInfo.minKey);
-    invariant(chunk);
-
-    // If the chunk is not found exactly as requested, the caller must have stale data
-    if (SimpleBSONObjComparator::kInstance.evaluate(chunk->getMin() != migrateInfo.minKey) ||
-        SimpleBSONObjComparator::kInstance.evaluate(chunk->getMax() != migrateInfo.maxKey)) {
-        return std::make_shared<Notification<RemoteCommandResponse>>(Status(
-            ErrorCodes::IncompatibleShardingMetadata,
-            stream() << "Chunk " << ChunkRange(migrateInfo.minKey, migrateInfo.maxKey).toString()
-                     << " does not exist."));
-    }
-
     const auto fromShardStatus = Grid::get(txn)->shardRegistry()->getShard(txn, migrateInfo.from);
     if (!fromShardStatus.isOK()) {
         return std::make_shared<Notification<RemoteCommandResponse>>(
@@ -495,12 +472,11 @@ shared_ptr<Notification<RemoteCommandResponse>> MigrationManager::_schedule(
     MoveChunkRequest::appendAsCommand(
         &builder,
         nss,
-        chunkManager->getVersion(),
+        migrateInfo.version,
         Grid::get(txn)->shardRegistry()->getConfigServerConnectionString(),
         migrateInfo.from,
         migrateInfo.to,
         ChunkRange(migrateInfo.minKey, migrateInfo.maxKey),
-        chunk->getLastmod(),
         maxChunkSizeBytes,
         secondaryThrottle,
         waitForDelete);
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 fa83a3bd69e..94188337f6b 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
@@ -142,7 +142,6 @@ protected:
             kDonorConnStr.getSetName(),
             kRecipientConnStr.getSetName(),
             chunkRange,
-            ChunkVersion(1, 0, OID::gen()),
             1024 * 1024,
             MigrationSecondaryThrottleOptions::create(MigrationSecondaryThrottleOptions::kDefault),
             false);
diff --git a/src/mongo/db/s/migration_source_manager.cpp b/src/mongo/db/s/migration_source_manager.cpp
index a66e6d63e72..22d6d259dab 100644
--- a/src/mongo/db/s/migration_source_manager.cpp
+++ b/src/mongo/db/s/migration_source_manager.cpp
@@ -91,15 +91,8 @@ MigrationSourceManager::MigrationSourceManager(OperationContext* txn,
             "Destination shard cannot be the same as source",
             _args.getFromShardId() != _args.getToShardId());
 
-    const auto& oss = OperationShardingState::get(txn);
-    uassert(ErrorCodes::InvalidOptions, "collection version is missing", oss.hasShardVersion());
-
-    // Even though the moveChunk command transmits a value in the operation's shardVersion field,
-    // this value does not actually contain the shard version, but the global collection version.
-    const ChunkVersion expectedCollectionVersion = oss.getShardVersion(getNss());
-
     log() << "Starting chunk migration " << redact(_args.toString())
-          << " with expected collection version " << expectedCollectionVersion;
+          << " with expected collection version epoch" << _args.getVersionEpoch();
 
     // Now that the collection is locked, snapshot the metadata and fetch the latest versions
     ShardingState* const shardingState = ShardingState::get(txn);
@@ -134,13 +127,13 @@ MigrationSourceManager::MigrationSourceManager(OperationContext* txn,
     const ChunkVersion collectionVersion = _collectionMetadata->getCollVersion();
 
     uassert(ErrorCodes::StaleEpoch,
-            str::stream() << "cannot move chunk " << _args.toString()
+            str::stream() << "cannot move chunk " << redact(_args.toString())
                           << " because collection may have been dropped. "
                           << "current epoch: "
                           << collectionVersion.epoch()
                           << ", cmd epoch: "
-                          << expectedCollectionVersion.epoch(),
-            expectedCollectionVersion.epoch() == collectionVersion.epoch());
+                          << _args.getVersionEpoch(),
+            _args.getVersionEpoch() == collectionVersion.epoch());
 
     // With nonzero shard version, we must have a coll version >= our shard version
     invariant(collectionVersion >= shardVersion);
@@ -155,9 +148,10 @@ MigrationSourceManager::MigrationSourceManager(OperationContext* txn,
     Status chunkValidateStatus = _collectionMetadata->checkChunkIsValid(chunkToMove);
     if (!chunkValidateStatus.isOK()) {
         uasserted(chunkValidateStatus.code(),
-                  str::stream() << "Unable to move chunk with arguments '" << _args.toString()
+                  str::stream() << "Unable to move chunk with arguments '"
+                                << redact(_args.toString())
                                 << "' due to error "
-                                << chunkValidateStatus.reason());
+                                << redact(chunkValidateStatus.reason()));
     }
 }