SERVER-30399 Add caching for $lookup non-correlated sub-pipeline prefix

1 files changed, 163 insertions, 0 deletions

diff --git a/src/mongo/db/pipeline/sequential_document_cache_test.cpp b/src/mongo/db/pipeline/sequential_document_cache_test.cpp
new file mode 100644
index 00000000000..5372a80ecfe
--- /dev/null
+++ b/src/mongo/db/pipeline/sequential_document_cache_test.cpp
@@ -0,0 +1,163 @@
+/**
+ * Copyright (C) 2017 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/pipeline/sequential_document_cache.h"
+
+#include "mongo/db/pipeline/document_value_test_util.h"
+#include "mongo/unittest/death_test.h"
+#include "mongo/unittest/unittest.h"
+
+namespace mongo {
+namespace {
+
+const size_t kCacheSizeBytes = 1024;
+
+TEST(SequentialDocumentCacheTest, CacheIsInBuildingModeUponInstantiation) {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+}
+
+TEST(SequentialDocumentCacheTest, CanAddDocumentsToCacheWhileBuilding) {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.add(DOC("_id" << 0));
+    cache.add(DOC("_id" << 1));
+
+    ASSERT_EQ(cache.count(), 2ul);
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotIterateCacheWhileBuilding, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.getNext();
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotRestartCacheIterationWhileBuilding, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.restartIteration();
+}
+
+TEST(SequentialDocumentCacheTest, CanIterateCacheAfterFreezing) {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.add(DOC("_id" << 0));
+    cache.add(DOC("_id" << 1));
+
+    ASSERT_EQ(cache.count(), 2ul);
+
+    cache.freeze();
+
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 0));
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 1));
+    ASSERT_FALSE(cache.getNext().is_initialized());
+}
+
+TEST(SequentialDocumentCacheTest, CanRestartCacheIterationAfterFreezing) {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.add(DOC("_id" << 0));
+    cache.add(DOC("_id" << 1));
+
+    ASSERT_EQ(cache.count(), 2ul);
+
+    cache.freeze();
+
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 0));
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 1));
+    ASSERT_FALSE(cache.getNext().is_initialized());
+
+    cache.restartIteration();
+
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 0));
+    ASSERT_DOCUMENT_EQ(*cache.getNext(), DOC("_id" << 1));
+    ASSERT_FALSE(cache.getNext().is_initialized());
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotAddDocumentsToCacheAfterFreezing, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    cache.freeze();
+
+    ASSERT(cache.isServing());
+
+    cache.add(DOC("_id" << 0));
+}
+
+TEST(SequentialDocumentCacheTest, ShouldAbandonCacheIfMaxSizeBytesExceeded) {
+    SequentialDocumentCache cache(0);
+    ASSERT(cache.isBuilding());
+
+    cache.add(DOC("_id" << 0));
+
+    ASSERT(cache.isAbandoned());
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotAddDocumentsToAbandonedCache, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    cache.abandon();
+
+    cache.add(DOC("_id" << 0));
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotFreezeCacheWhenAbandoned, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    cache.abandon();
+
+    cache.freeze();
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotRestartCacheIterationWhenAbandoned, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.abandon();
+
+    cache.restartIteration();
+}
+
+DEATH_TEST(SequentialDocumentCacheTest, CannotCallGetNextWhenAbandoned, "invariant") {
+    SequentialDocumentCache cache(kCacheSizeBytes);
+    ASSERT(cache.isBuilding());
+
+    cache.add(DOC("_id" << 0));
+    cache.add(DOC("_id" << 1));
+
+    cache.abandon();
+
+    cache.getNext();
+}
+
+}  // namespace
+}  // namespace mongo