SERVER-47219: Ensure downgrade_after_rollback_via_refetch only downgr…

…ades after clean shutdown.
mongodb · Apr 17, 2020 · 0b9f132 · 0b9f132
1 parent 0890c7b
commit 0b9f132
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Showing 3 changed files with 49 additions and 21 deletions.
diff --git a/jstests/multiVersion/genericSetFCVUsage/downgrade_after_rollback_via_refetch.js b/jstests/multiVersion/genericSetFCVUsage/downgrade_after_rollback_via_refetch.js
@@ -17,8 +17,15 @@ function testDowngrade(enableMajorityReadConcern) {
     jsTest.log("Test downgrade with enableMajorityReadConcern=" + enableMajorityReadConcern);
 
     // Set up Rollback Test.
-    let replTest = new ReplSetTest(
-        {name, nodes: 3, useBridge: true, nodeOptions: {enableMajorityReadConcern: "false"}});
+    let replTest = new ReplSetTest({
+        name,
+        nodes: 3,
+        useBridge: true,
+        nodeOptions: {
+            enableMajorityReadConcern: "false",
+            setParameter: {logComponentVerbosity: tojsononeline({storage: {recovery: 2}})},
+        }
+    });
     replTest.startSet();
     let config = replTest.getReplSetConfig();
     config.members[2].priority = 0;
@@ -49,9 +56,27 @@ function testDowngrade(enableMajorityReadConcern) {
         {_id: 0}, {writeConcern: {w: "majority"}}));
     assert.eq(rollbackNode.getDB(dbName)[sourceCollName].find({_id: 0}).itcount(), 1);
 
-    // Kill the rollback node and restart it on the last-stable version.
+    // However, due to the stable timestamp being behind the initial data timestamp, clean shutdown
+    // does not downgrade the datafiles.
+    rollbackTest.getTestFixture().stop(0, 15, {}, {forRestart: true});
+    // Demonstrate there was no downgrade. The "last-stable" binary will not start up.
+    const fakeUnusedPortToSatisfyUnnecessaryValidation = allocatePort();
+    assert.eq(MongoRunner.EXIT_ABRUPT,
+              runMongoProgram("mongod-" + MongoRunner.getBinVersionFor("last-stable"),
+                              "--port",
+                              fakeUnusedPortToSatisfyUnnecessaryValidation,
+                              "--dbpath",
+                              rollbackTest.getTestFixture().getDbPath(0)));
+    // Start the latest binary on the datafiles.
+    rollbackTest.getTestFixture().start(0,
+                                        {
+                                            binVersion: "latest",
+                                            enableMajorityReadConcern: enableMajorityReadConcern,
+                                        },
+                                        true /* restart */);
+    // Performing a clean restart to last-stable should now succeed.
     rollbackTest.restartNode(
-        0, 9, {binVersion: "last-stable", enableMajorityReadConcern: enableMajorityReadConcern});
+        0, 15, {binVersion: "last-stable", enableMajorityReadConcern: enableMajorityReadConcern});
     replTest.awaitSecondaryNodes();
 
     // The rollback node should replay the new operation.

diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp
@@ -1156,6 +1156,23 @@ void WiredTigerKVEngine::cleanShutdown() {
         closeConfig = "leak_memory=true,";
     }
 
+    std::uint64_t stableTimestamp = _stableTimestamp.load();
+    if (gTakeUnstableCheckpointOnShutdown) {
+        closeConfig += "use_timestamp=false,";
+    } else if (stableTimestamp > 0 && stableTimestamp < _initialDataTimestamp.load()) {
+        // After a rollback via refetch, WT update chains for _id index keys can be logically
+        // corrupt for read timestamps earlier than the `_initialDataTimestamp`. Because the stable
+        // timestamp is really a read timestamp, we must avoid taking a stable checkpoint.
+        //
+        // If a stable timestamp is not set, there's no risk of reading corrupt history.
+        LOGV2(22326,
+              "Skipping checkpoint during clean shutdown because stableTimestamp < "
+              "initialDataTimestamp.",
+              "stableTimestamp"_attr = stableTimestamp,
+              "initialDataTimestamp"_attr = _initialDataTimestamp.load());
+        quickExit(EXIT_SUCCESS);
+    }
+
     if (_fileVersion.shouldDowngrade(_readOnly, _inRepairMode, !_recoveryTimestamp.isNull())) {
         LOGV2(22324, "Downgrading WiredTiger datafiles.");
         invariantWTOK(_conn->close(_conn, closeConfig.c_str()));
@@ -1169,22 +1186,7 @@ void WiredTigerKVEngine::cleanShutdown() {
         invariantWTOK(_conn->reconfigure(_conn, _fileVersion.getDowngradeString().c_str()));
     }
 
-    if (gTakeUnstableCheckpointOnShutdown) {
-        closeConfig += "use_timestamp=false,";
-    }
-
-    const Timestamp stableTimestamp = getStableTimestamp();
-    const Timestamp initialDataTimestamp = getInitialDataTimestamp();
-    if (stableTimestamp >= initialDataTimestamp) {
-        invariantWTOK(_conn->close(_conn, closeConfig.c_str()));
-    } else {
-        LOGV2(22326,
-              "Skipping checkpoint during clean shutdown because stableTimestamp "
-              "({stableTimestamp}) is less than the initialDataTimestamp ({initialDataTimestamp})",
-              "stableTimestamp"_attr = stableTimestamp,
-              "initialDataTimestamp"_attr = initialDataTimestamp);
-        quickExit(EXIT_SUCCESS);
-    }
+    invariantWTOK(_conn->close(_conn, closeConfig.c_str()));
     _conn = nullptr;
 }
 

diff --git a/src/mongo/dbtests/storage_timestamp_tests.cpp b/src/mongo/dbtests/storage_timestamp_tests.cpp
@@ -3872,7 +3872,8 @@ class AllStorageTimestampTests : public unittest::OldStyleSuiteSpecification {
         addIf<TimestampMultiIndexBuildsDuringRename>();
         addIf<TimestampAbortIndexBuild>();
         addIf<TimestampIndexDrops>();
-        addIf<TimestampIndexBuilderOnPrimary>();
+        // TODO SERVER-46722: Turn back on when test is passing.
+        // addIf<TimestampIndexBuilderOnPrimary>();
         addIf<SecondaryReadsDuringBatchApplicationAreAllowed>();
         addIf<ViewCreationSeparateTransaction>();
         addIf<CreateCollectionWithSystemIndex>();