SERVER-32885 Overlap chunk clone application on the donor with fetching documents from the recipient

Repushed to update error codes

1 files changed, 160 insertions, 0 deletions

diff --git a/src/mongo/db/s/migration_destination_manager_test.cpp b/src/mongo/db/s/migration_destination_manager_test.cpp
new file mode 100644
index 00000000000..6dd3d456a2f
--- /dev/null
+++ b/src/mongo/db/s/migration_destination_manager_test.cpp
@@ -0,0 +1,160 @@
+/**
+ *    Copyright (C) 2018 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects
+ *    for all of the code used other than as permitted herein. If you modify
+ *    file(s) with this exception, you may extend this exception to your
+ *    version of the file(s), but you are not obligated to do so. If you do not
+ *    wish to do so, delete this exception statement from your version. If you
+ *    delete this exception statement from all source files in the program,
+ *    then also delete it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/s/migration_destination_manager.h"
+#include "mongo/s/shard_server_test_fixture.h"
+#include "mongo/unittest/unittest.h"
+
+namespace mongo {
+namespace {
+
+using unittest::assertGet;
+
+class MigrationDestinationManagerTest : public ShardServerTestFixture {
+protected:
+    /**
+     * Instantiates a BSON object in which both "_id" and "X" are set to value.
+     */
+    static BSONObj createDocument(int value) {
+        return BSON("_id" << value << "X" << value);
+    }
+
+    /**
+     * Creates a list of documents to clone.
+     */
+    static std::vector<BSONObj> createDocumentsToClone() {
+        return {createDocument(1), createDocument(2), createDocument(3)};
+    }
+
+    /**
+     * Creates a list of documents to clone and converts it to a BSONArray.
+     */
+    static BSONArray createDocumentsToCloneArray() {
+        BSONArrayBuilder arrayBuilder;
+        for (auto& doc : createDocumentsToClone()) {
+            arrayBuilder.append(doc);
+        }
+        return arrayBuilder.arr();
+    }
+};
+
+// Tests that documents will ferry from the fetch logic to the insert logic successfully.
+TEST_F(MigrationDestinationManagerTest, CloneDocumentsFromDonorWorksCorrectly) {
+    bool ranOnce = false;
+
+    auto fetchBatchFn = [&](OperationContext* opCtx) {
+        BSONObjBuilder fetchBatchResultBuilder;
+
+        if (ranOnce) {
+            fetchBatchResultBuilder.append("objects", BSONObj());
+        } else {
+            ranOnce = true;
+            fetchBatchResultBuilder.append("objects", createDocumentsToCloneArray());
+        }
+
+        return fetchBatchResultBuilder.obj();
+    };
+
+    std::vector<BSONObj> resultDocs;
+
+    auto insertBatchFn = [&](OperationContext* opCtx, BSONObjIterator docs) {
+        while (docs.more()) {
+            resultDocs.push_back(docs.next().Obj().getOwned());
+        }
+    };
+
+    MigrationDestinationManager::cloneDocumentsFromDonor(
+        operationContext(), insertBatchFn, fetchBatchFn);
+
+    std::vector<BSONObj> originalDocs = createDocumentsToClone();
+
+    ASSERT_EQ(originalDocs.size(), resultDocs.size());
+
+    for (auto originalDocsIt = originalDocs.begin(), resultDocsIt = resultDocs.begin();
+         originalDocsIt != originalDocs.end() && resultDocsIt != resultDocs.end();
+         ++originalDocsIt, ++resultDocsIt) {
+        ASSERT_BSONOBJ_EQ(*originalDocsIt, *resultDocsIt);
+    }
+}
+
+// Tests that an exception in the fetch logic will successfully throw an exception on the main
+// thread.
+TEST_F(MigrationDestinationManagerTest, CloneDocumentsThrowsFetchErrors) {
+    bool ranOnce = false;
+
+    auto fetchBatchFn = [&](OperationContext* opCtx) {
+        BSONObjBuilder fetchBatchResultBuilder;
+
+        if (ranOnce) {
+            uasserted(ErrorCodes::NetworkTimeout, "network error");
+        }
+
+        ranOnce = true;
+        fetchBatchResultBuilder.append("objects", createDocumentsToCloneArray());
+
+        return fetchBatchResultBuilder.obj();
+    };
+
+    auto insertBatchFn = [&](OperationContext* opCtx, BSONObjIterator docs) {};
+
+    ASSERT_THROWS_CODE_AND_WHAT(MigrationDestinationManager::cloneDocumentsFromDonor(
+                                    operationContext(), insertBatchFn, fetchBatchFn),
+                                DBException,
+                                ErrorCodes::NetworkTimeout,
+                                "network error");
+}
+
+// Tests that an exception in the insertion logic will successfully throw an exception on the
+// main thread.
+TEST_F(MigrationDestinationManagerTest, CloneDocumentsCatchesInsertErrors) {
+    auto fetchBatchFn = [&](OperationContext* opCtx) {
+        BSONObjBuilder fetchBatchResultBuilder;
+        fetchBatchResultBuilder.append("objects", createDocumentsToCloneArray());
+        return fetchBatchResultBuilder.obj();
+    };
+
+    auto insertBatchFn = [&](OperationContext* opCtx, BSONObjIterator docs) {
+        uasserted(ErrorCodes::FailedToParse, "insertion error");
+    };
+
+    // Since the error is thrown on another thread, the message becomes "operation was interrupted"
+    // on the main thread.
+
+    ASSERT_THROWS_CODE_AND_WHAT(MigrationDestinationManager::cloneDocumentsFromDonor(
+                                    operationContext(), insertBatchFn, fetchBatchFn),
+                                DBException,
+                                ErrorCodes::FailedToParse,
+                                "operation was interrupted");
+
+    ASSERT_EQ(operationContext()->getKillStatus(), ErrorCodes::FailedToParse);
+}
+
+}  // namespace
+}  // namespace mongo