SERVER-52950 recoverFromOplogAsStandalone mode must not start oplog truncater thread

(cherry picked from commit 3417215850d7a577452552499ea55d1872199d74)

2 files changed, 68 insertions, 2 deletions

diff --git a/jstests/noPassthrough/check_for_oplog_cap_maintainer_thread.js b/jstests/noPassthrough/check_for_oplog_cap_maintainer_thread.js
new file mode 100644
index 00000000000..abcfdd574f3
--- /dev/null
+++ b/jstests/noPassthrough/check_for_oplog_cap_maintainer_thread.js
@@ -0,0 +1,58 @@
+/**
+ * Checks that the oplog cap maintainer thread is started and the oplog stones calculation is
+ * performed under normal startup circumstances. Both of these operations should not be done when
+ * starting up with any of the following modes:
+ *     - readonly
+ *     - repair
+ *     - recoverFromOplogAsStandalone
+ *
+ * @tags: [requires_replication, requires_persistence]
+ */
+(function() {
+    "use strict";
+
+    // Verify that the oplog cap maintainer thread is running under normal circumstances.
+    jsTestLog("Testing single node replica set mode");
+    const rst = new ReplSetTest({nodes: 1, nodeOptions: {setParameter: {logLevel: 1}}});
+    rst.startSet();
+    rst.initiate();
+
+    const primary = rst.getPrimary();
+
+    checkLog.contains(primary, "OplogTruncaterThread started");
+    checkLog.contains(primary, "WiredTiger record store oplog processing took");
+
+    rst.stopSet(/*signal=*/null, /*forRestart=*/true);
+
+    // A subset of startup options prevent the oplog cap maintainer thread from being started. These
+    // startup options are currently limited to readOnly, recoverFromOplogAsStandalone and repair.
+    function verifyOplogCapMaintainerThreadNotStarted(log) {
+        const threadRegex = new RegExp("OplogTruncaterThread started");
+        const oplogStonesRegex = new RegExp("WiredTiger record store oplog processing took");
+
+        assert(!threadRegex.test(log));
+        assert(!oplogStonesRegex.test(log));
+    }
+
+    jsTestLog("Testing recoverFromOplogAsStandalone mode");
+    clearRawMongoProgramOutput();
+    let conn = MongoRunner.runMongod({
+        dbpath: primary.dbpath,
+        noCleanData: true,
+        setParameter: {recoverFromOplogAsStandalone: true, logLevel: 1},
+    });
+    assert(conn);
+    MongoRunner.stopMongod(conn);
+    verifyOplogCapMaintainerThreadNotStarted(rawMongoProgramOutput());
+
+    jsTestLog("Testing repair mode");
+    clearRawMongoProgramOutput();
+    conn = MongoRunner.runMongod({
+        dbpath: primary.dbpath,
+        noCleanData: true,
+        repair: "",
+        setParameter: {logLevel: 1},
+    });
+    assert(!conn);
+    verifyOplogCapMaintainerThreadNotStarted(rawMongoProgramOutput());
+}());
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_mongod.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_mongod.cpp
index fdc45e0c54f..81696dba8f4 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_mongod.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store_mongod.cpp
@@ -129,6 +129,7 @@ public:
 
     virtual void run() {
         Client::initThread(_name.c_str());
+        LOG(1) << "OplogTruncaterThread started";
         ON_BLOCK_EXIT([] { Client::destroy(); });
 
         while (!globalInShutdownDeprecated()) {
@@ -148,9 +149,16 @@ bool initRsOplogBackgroundThread(StringData ns) {
         return false;
     }
 
-    if (storageGlobalParams.repair || storageGlobalParams.readOnly) {
+    // When starting up with recoverFromOplogAsStandalone=true, the readOnly flag is initially set
+    // to false to allow oplog recovery to run and perform its necessary writes. After recovery is
+    // complete, the readOnly flag gets flipped to true. Because of this subtlety, we avoid
+    // calculating the oplog stones when recoverFromOplogAsStandalone=true as the RecordStore
+    // construction for the oplog happens before the readOnly flag gets flipped to true.
+    if (storageGlobalParams.repair || storageGlobalParams.readOnly ||
+        repl::ReplSettings::shouldRecoverFromOplogAsStandalone()) {
         LOG(1) << "not starting OplogTruncaterThread for " << ns
-               << " because we are either in repair or read-only mode";
+               << " because we are either in repair mode, read-only mode or recovering from the"
+               << " oplog in standalone mode";
         return false;
     }