SERVER-35612 Implement ChunkWritesTracker with unit tests, make ChunkInfo use it

1 files changed, 143 insertions, 0 deletions

diff --git a/src/mongo/s/chunk_writes_tracker_test.cpp b/src/mongo/s/chunk_writes_tracker_test.cpp
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+++ b/src/mongo/s/chunk_writes_tracker_test.cpp
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+/**
+ * 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/s/chunk_writes_tracker.h"
+
+#include "mongo/unittest/death_test.h"
+#include "mongo/unittest/unittest.h"
+
+
+namespace mongo {
+
+TEST(ChunkWritesTrackerTest, BytesWrittenStartsAtZero) {
+    ChunkWritesTracker wt;
+    ASSERT_EQ(wt.getBytesWritten(), 0ull);
+}
+
+TEST(ChunkWritesTrackerTest, AddBytesWrittenCorrectlyAddsBytes) {
+    ChunkWritesTracker wt;
+    uint64_t bytesToAdd{4};
+    wt.addBytesWritten(bytesToAdd);
+    ASSERT_EQ(wt.getBytesWritten(), bytesToAdd);
+}
+
+TEST(ChunkWritesTrackerTest, ClearBytesWrittenSetsBytesToZero) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    wt.clearBytesWritten();
+    ASSERT_EQ(wt.getBytesWritten(), 0ull);
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsTrueWithBytesWrittenAndMaxChunkSizeZero) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    uint64_t maxChunkSize{0};
+    ASSERT_TRUE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsFalseWithNoBytesWrittenAndMaxChunkSizeZero) {
+    ChunkWritesTracker wt;
+    uint64_t maxChunkSize{0};
+    ASSERT_FALSE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsTrueWithBytesWrittenGreaterThanMaxChunkSize) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    uint64_t maxChunkSize{3};
+    ASSERT_TRUE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsFalseWithBytesWrittenLessThanThreshold) {
+    ChunkWritesTracker wt;
+    uint64_t maxChunkSize{10};
+    auto expectedCutoff = maxChunkSize / ChunkWritesTracker::kSplitTestFactor;
+    wt.addBytesWritten(expectedCutoff - 1);
+    ASSERT_FALSE(wt.shouldSplit(maxChunkSize));
+    wt.addBytesWritten(1ul);
+    ASSERT_FALSE(wt.shouldSplit(maxChunkSize));
+    wt.addBytesWritten(1ul);
+    ASSERT_TRUE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsFalseWithBytesWrittenEqualToThreshold) {
+    ChunkWritesTracker wt;
+    uint64_t maxChunkSize{10};
+    auto expectedCutoff = maxChunkSize / ChunkWritesTracker::kSplitTestFactor;
+    wt.addBytesWritten(expectedCutoff);
+    ASSERT_FALSE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsFalseWithBytesWrittenGreaterThanThreshold) {
+    ChunkWritesTracker wt;
+    uint64_t maxChunkSize{10};
+    auto expectedCutoff = maxChunkSize / ChunkWritesTracker::kSplitTestFactor;
+    wt.addBytesWritten(expectedCutoff + 1);
+    ASSERT_TRUE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsFalseWhenSplitLockAcquired) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    wt.acquireSplitLock();
+    uint64_t maxChunkSize{0};
+    ASSERT_FALSE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, ShouldSplitReturnsTrueAfterSplitLockReleased) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    wt.acquireSplitLock();
+    wt.releaseSplitLock();
+    uint64_t maxChunkSize{0};
+    ASSERT_TRUE(wt.shouldSplit(maxChunkSize));
+}
+
+TEST(ChunkWritesTrackerTest, AcquireSplitLockReturnsFalseAfterReturningTrue) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    ASSERT_TRUE(wt.acquireSplitLock());
+    ASSERT_FALSE(wt.acquireSplitLock());
+}
+
+TEST(ChunkWritesTrackerTest, AcquireSplitLockThenReleaseThenReacquireReturnsTrue) {
+    ChunkWritesTracker wt;
+    wt.addBytesWritten(4ull);
+    wt.acquireSplitLock();
+    wt.releaseSplitLock();
+    ASSERT_TRUE(wt.acquireSplitLock());
+}
+
+DEATH_TEST(ChunkWritesTrackerTest, ReleaseSplitLockWithoutAcquiringErrors, "Invariant failure") {
+    ChunkWritesTracker wt;
+    wt.releaseSplitLock();
+}
+
+}  // namespace mongo