From 2f67f3c66271e724b48afa2db88e8b6c3317f6ab Mon Sep 17 00:00:00 2001
From: Dianna Hohensee <dianna.hohensee@10gen.com>
Date: Fri, 11 Jan 2019 09:52:44 -0500
Subject: [PATCH] SERVER-33161 make the second phase of index two-phase drop
 occur when drop reaches checkpointed instead of oldest

---
 src/mongo/db/storage/kv/kv_storage_engine.cpp | 20 +++++++++----------
 src/mongo/db/storage/kv/kv_storage_engine.h   |  8 ++++----
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/mongo/db/storage/kv/kv_storage_engine.cpp b/src/mongo/db/storage/kv/kv_storage_engine.cpp
index a09d4c7a743d1..c7e09dfcf7925 100644
--- a/src/mongo/db/storage/kv/kv_storage_engine.cpp
+++ b/src/mongo/db/storage/kv/kv_storage_engine.cpp
@@ -89,9 +89,9 @@ KVStorageEngine::KVStorageEngine(
       _options(std::move(options)),
       _databaseCatalogEntryFactory(std::move(databaseCatalogEntryFactory)),
       _dropPendingIdentReaper(engine),
-      _oldestTimestampListener(
-          TimestampMonitor::TimestampType::kOldest,
-          [this](Timestamp timestamp) { _onOldestTimestampChanged(timestamp); }),
+      _checkpointTimestampListener(
+          TimestampMonitor::TimestampType::kCheckpoint,
+          [this](Timestamp timestamp) { _onCheckpointTimestampChanged(timestamp); }),
       _supportsDocLocking(_engine->supportsDocLocking()),
       _supportsDBLocking(_engine->supportsDBLocking()),
       _supportsCappedCollections(_engine->supportsCappedCollections()) {
@@ -477,7 +477,7 @@ std::string KVStorageEngine::getFilesystemPathForDb(const std::string& dbName) c
 
 void KVStorageEngine::cleanShutdown() {
     if (_timestampMonitor) {
-        _timestampMonitor->removeListener(&_oldestTimestampListener);
+        _timestampMonitor->removeListener(&_checkpointTimestampListener);
     }
 
     for (DBMap::const_iterator it = _dbs.begin(); it != _dbs.end(); ++it) {
@@ -501,7 +501,7 @@ void KVStorageEngine::finishInit() {
         _timestampMonitor = std::make_unique<TimestampMonitor>(
             _engine.get(), getGlobalServiceContext()->getPeriodicRunner());
         _timestampMonitor->startup();
-        _timestampMonitor->addListener(&_oldestTimestampListener);
+        _timestampMonitor->addListener(&_checkpointTimestampListener);
     }
 }
 
@@ -791,17 +791,17 @@ void KVStorageEngine::addDropPendingIdent(const Timestamp& dropTimestamp,
     _dropPendingIdentReaper.addDropPendingIdent(dropTimestamp, nss, ident);
 }
 
-void KVStorageEngine::_onOldestTimestampChanged(const Timestamp& oldestTimestamp) {
-    if (oldestTimestamp.isNull()) {
+void KVStorageEngine::_onCheckpointTimestampChanged(const Timestamp& checkpointTimestamp) {
+    if (checkpointTimestamp.isNull()) {
         return;
     }
     // No drop-pending idents present if getEarliestDropTimestamp() returns boost::none.
     if (auto earliestDropTimestamp = _dropPendingIdentReaper.getEarliestDropTimestamp()) {
-        if (oldestTimestamp > *earliestDropTimestamp) {
+        if (checkpointTimestamp > *earliestDropTimestamp) {
             log() << "Removing drop-pending idents with drop timestamps before: "
-                  << oldestTimestamp;
+                  << checkpointTimestamp;
             auto opCtx = cc().makeOperationContext();
-            _dropPendingIdentReaper.dropIdentsOlderThan(opCtx.get(), oldestTimestamp);
+            _dropPendingIdentReaper.dropIdentsOlderThan(opCtx.get(), checkpointTimestamp);
         }
     }
 }
diff --git a/src/mongo/db/storage/kv/kv_storage_engine.h b/src/mongo/db/storage/kv/kv_storage_engine.h
index df80e48746fe7..1bd52d7e522fb 100644
--- a/src/mongo/db/storage/kv/kv_storage_engine.h
+++ b/src/mongo/db/storage/kv/kv_storage_engine.h
@@ -386,9 +386,9 @@ class KVStorageEngine final : public KVStorageEngineInterface, public StorageEng
     void _dumpCatalog(OperationContext* opCtx);
 
     /**
-     * Called when the oldest timestamp advances in the KVEngine.
+     * Called when the checkpoint timestamp advances in the KVEngine.
      */
-    void _onOldestTimestampChanged(const Timestamp& oldestTimestamp);
+    void _onCheckpointTimestampChanged(const Timestamp& checkpointTimestamp);
 
     class RemoveDBChange;
 
@@ -402,8 +402,8 @@ class KVStorageEngine final : public KVStorageEngineInterface, public StorageEng
     // Manages drop-pending idents. Requires access to '_engine'.
     KVDropPendingIdentReaper _dropPendingIdentReaper;
 
-    // Listener for oldest timestamp changes.
-    TimestampMonitor::TimestampListener _oldestTimestampListener;
+    // Listener for checkpoint timestamp changes.
+    TimestampMonitor::TimestampListener _checkpointTimestampListener;
 
     const bool _supportsDocLocking;
     const bool _supportsDBLocking;