SERVER-45900 Check for unsharded collection when submitting range deletion task

2 files changed, 86 insertions, 8 deletions

diff --git a/src/mongo/db/s/migration_util.cpp b/src/mongo/db/s/migration_util.cpp
index ff3d10e6537..58f9198057c 100644
--- a/src/mongo/db/s/migration_util.cpp
+++ b/src/mongo/db/s/migration_util.cpp
@@ -144,15 +144,18 @@ ExecutorFuture<bool> submitRangeDeletionTask(OperationContext* opCtx,
             autoColl.emplace(opCtx, deletionTask.getNss(), MODE_IS);
 
             auto css = CollectionShardingRuntime::get(opCtx, deletionTask.getNss());
-            if (!css->getCurrentMetadataIfKnown() ||
+            if (!css->getCurrentMetadataIfKnown() || !css->getCurrentMetadata()->isSharded() ||
                 !css->getCurrentMetadata()->uuidMatches(deletionTask.getCollectionUuid())) {
-                // If the collection's filtering metadata is not known or its UUID does not match
-                // the UUID of the deletion task, force a filtering metadata refresh once, because
-                // this node may have just stepped up and therefore may have a stale cache.
+                // If the collection's filtering metadata is not known, is unsharded, or its UUID
+                // does not match the UUID of the deletion task, force a filtering metadata refresh
+                // once, because this node may have just stepped up and therefore may have a stale
+                // cache.
                 LOG(0) << "Filtering metadata for namespace in deletion task "
                        << deletionTask.toBSON()
                        << (css->getCurrentMetadataIfKnown()
-                               ? " has UUID that does not match UUID of the deletion task"
+                               ? (css->getCurrentMetadata()->isSharded()
+                                      ? " has UUID that does not match UUID of the deletion task"
+                                      : " is unsharded")
                                : " is not known")
                        << ", forcing a refresh of " << deletionTask.getNss();
 
@@ -173,14 +176,16 @@ ExecutorFuture<bool> submitRangeDeletionTask(OperationContext* opCtx,
             }
 
             autoColl.emplace(opCtx, deletionTask.getNss(), MODE_IS);
-            if (!css->getCurrentMetadataIfKnown() ||
+            if (!css->getCurrentMetadataIfKnown() || !css->getCurrentMetadata()->isSharded() ||
                 !css->getCurrentMetadata()->uuidMatches(deletionTask.getCollectionUuid())) {
                 LOG(0) << "Even after forced refresh, filtering metadata for namespace in deletion "
                           "task "
                        << deletionTask.toBSON()
                        << (css->getCurrentMetadataIfKnown()
-                               ? "has UUID that does not match UUID of the deletion task"
-                               : "is not known")
+                               ? (css->getCurrentMetadata()->isSharded()
+                                      ? " has UUID that does not match UUID of the deletion task"
+                                      : " is unsharded")
+                               : " is not known")
                        << ", deleting the task.";
 
                 autoColl.reset();
diff --git a/src/mongo/db/s/migration_util_test.cpp b/src/mongo/db/s/migration_util_test.cpp
index 14547873f36..fa8b6197552 100644
--- a/src/mongo/db/s/migration_util_test.cpp
+++ b/src/mongo/db/s/migration_util_test.cpp
@@ -534,6 +534,54 @@ TEST_F(SubmitRangeDeletionTaskTest,
     ASSERT_EQ(store.count(opCtx), 0);
 }
 
+TEST_F(SubmitRangeDeletionTaskTest, FailsAndDeletesTaskIfNamespaceIsUnshardedEvenAfterRefresh) {
+    auto opCtx = operationContext();
+
+    auto deletionTask = createDeletionTask(kNss, kDefaultUUID, 0, 10);
+
+    PersistentTaskStore<RangeDeletionTask> store(opCtx, NamespaceString::kRangeDeletionNamespace);
+    store.add(opCtx, deletionTask);
+    ASSERT_EQ(store.count(opCtx), 1);
+
+    // Make the refresh triggered by submitting the task return an empty result when loading the
+    // collection so it is considered unsharded.
+    _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
+    _mockCatalogCacheLoader->setCollectionRefreshReturnValue(
+        Status(ErrorCodes::NamespaceNotFound, "dummy errmsg"));
+
+    auto submitTaskFuture = migrationutil::submitRangeDeletionTask(opCtx, deletionTask);
+
+    // The task should not have been submitted, and the task's entry should have been removed from
+    // the persistent store.
+    ASSERT_FALSE(submitTaskFuture.get(opCtx));
+    ASSERT_EQ(store.count(opCtx), 0);
+}
+
+TEST_F(SubmitRangeDeletionTaskTest,
+       FailsAndDeletesTaskIfNamespaceIsUnshardedBeforeAndAfterRefresh) {
+    auto opCtx = operationContext();
+
+    auto deletionTask = createDeletionTask(kNss, kDefaultUUID, 0, 10);
+
+    PersistentTaskStore<RangeDeletionTask> store(opCtx, NamespaceString::kRangeDeletionNamespace);
+    store.add(opCtx, deletionTask);
+    ASSERT_EQ(store.count(opCtx), 1);
+
+    // Mock an empty result for the task's collection and force a refresh so the node believes the
+    // collection is unsharded.
+    _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
+    _mockCatalogCacheLoader->setCollectionRefreshReturnValue(
+        Status(ErrorCodes::NamespaceNotFound, "dummy errmsg"));
+    forceShardFilteringMetadataRefresh(opCtx, kNss, true);
+
+    auto submitTaskFuture = migrationutil::submitRangeDeletionTask(opCtx, deletionTask);
+
+    // The task should not have been submitted, and the task's entry should have been removed from
+    // the persistent store.
+    ASSERT_FALSE(submitTaskFuture.get(opCtx));
+    ASSERT_EQ(store.count(opCtx), 0);
+}
+
 TEST_F(SubmitRangeDeletionTaskTest, SucceedsIfFilteringMetadataUUIDMatchesTaskUUID) {
     auto opCtx = operationContext();
 
@@ -574,6 +622,31 @@ TEST_F(
 }
 
 TEST_F(SubmitRangeDeletionTaskTest,
+       SucceedsIfTaskNamespaceInitiallyUnshardedButUUIDMatchesAfterRefresh) {
+    auto opCtx = operationContext();
+
+    // Force a metadata refresh with no collection entry so the node believes the namespace is
+    // unsharded when the task is submitted.
+    _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
+    _mockCatalogCacheLoader->setCollectionRefreshReturnValue(
+        Status(ErrorCodes::NamespaceNotFound, "dummy errmsg"));
+    forceShardFilteringMetadataRefresh(opCtx, kNss, true);
+
+    auto deletionTask = createDeletionTask(kNss, kDefaultUUID, 0, 10);
+
+    // Make the refresh triggered by submitting the task return a UUID that matches the task's UUID.
+    auto matchingColl = makeCollectionType(kDefaultUUID, kEpoch);
+    _mockCatalogCacheLoader->setCollectionRefreshReturnValue(matchingColl);
+    _mockCatalogCacheLoader->setChunkRefreshReturnValue(
+        makeChangedChunks(ChunkVersion(10, 0, kEpoch)));
+    _mockCatalogClient->setCollections({matchingColl});
+
+    // The task should have been submitted successfully.
+    auto submitTaskFuture = migrationutil::submitRangeDeletionTask(opCtx, deletionTask);
+    ASSERT(submitTaskFuture.get(opCtx));
+}
+
+TEST_F(SubmitRangeDeletionTaskTest,
        SucceedsIfFilteringMetadataUUIDInitiallyDifferentFromTaskUUIDButMatchesAfterRefresh) {
     auto opCtx = operationContext();