SERVER-44821 accessing db.system.profile and currentOp storage stats should not conflict with slow oplog application

(cherry picked from commit 87bcfd4931e002bcfdb563d58bde06e32aca1d8d)

3 files changed, 70 insertions, 0 deletions

diff --git a/jstests/noPassthrough/currentop_secondary_slow_op.js b/jstests/noPassthrough/currentop_secondary_slow_op.js
new file mode 100644
index 00000000000..66e83520056
--- /dev/null
+++ b/jstests/noPassthrough/currentop_secondary_slow_op.js
@@ -0,0 +1,64 @@
+/**
+ * Confirms slow currentOp logging does not conflict with applying an oplog batch.
+ * @tags: [requires_replication]
+ */
+(function() {
+"use strict";
+
+const rst = new ReplSetTest({
+    nodes: [
+        {},
+        {
+            // Disallow elections on secondary.
+            rsConfig: {
+                priority: 0,
+                votes: 0,
+            },
+            slowms: 30000,  // Don't log slow operations on secondary.
+        },
+    ]
+});
+const nodes = rst.startSet();
+rst.initiate();
+
+const primary = rst.getPrimary();
+const testDB = primary.getDB('test');
+const coll = testDB.getCollection('test');
+
+assert.commandWorked(coll.insert({_id: 'a'}));
+
+const secondary = rst.getSecondary();
+const secondaryDB = secondary.getDB(testDB.getName());
+assert.commandWorked(secondaryDB.adminCommand({
+    configureFailPoint: 'hangAfterCollectionInserts',
+    mode: 'alwaysOn',
+    data: {
+        collectionNS: coll.getFullName(),
+        first_id: 'b',
+    },
+}));
+
+try {
+    assert.commandWorked(coll.insert({_id: 'b'}));
+    checkLog.contains(secondary,
+                      'hangAfterCollectionInserts fail point enabled for ' + coll.getFullName());
+
+    jsTestLog('Running currentOp() with slow operation logging.');
+    // Lower slowms to make currentOp() log slow operation while the secondary is procesing the
+    // commitIndexBuild oplog entry during oplog application.
+    // Use admin db on secondary to avoid lock conflict with inserts in test db.
+    const secondaryAdminDB = secondaryDB.getSiblingDB('admin');
+    const profileResult = assert.commandWorked(secondaryAdminDB.setProfilingLevel(0, {slowms: -1}));
+    jsTestLog('Configured profiling to always log slow ops: ' + tojson(profileResult));
+    const currentOpResult = assert.commandWorked(secondaryAdminDB.currentOp());
+    jsTestLog('currentOp() with slow operation logging: ' + tojson(currentOpResult));
+    assert.commandWorked(
+        secondaryAdminDB.setProfilingLevel(profileResult.was, {slowms: profileResult.slowms}));
+    jsTestLog('Completed currentOp() with slow operation logging.');
+} finally {
+    assert.commandWorked(
+        secondaryDB.adminCommand({configureFailPoint: 'hangAfterCollectionInserts', mode: 'off'}));
+}
+
+rst.stopSet();
+})();
diff --git a/src/mongo/db/commands/dbcommands_d.cpp b/src/mongo/db/commands/dbcommands_d.cpp
index f94edb2992f..626247acb3b 100644
--- a/src/mongo/db/commands/dbcommands_d.cpp
+++ b/src/mongo/db/commands/dbcommands_d.cpp
@@ -120,6 +120,9 @@ protected:
         const bool readOnly = (profilingLevel < 0 || profilingLevel > 2);
         const LockMode dbMode = readOnly ? MODE_S : MODE_X;
 
+        // Accessing system.profile collection should not conflict with oplog application.
+        ShouldNotConflictWithSecondaryBatchApplicationBlock shouldNotConflictBlock(
+            opCtx->lockState());
         AutoGetDb ctx(opCtx, dbName, dbMode);
         Database* db = ctx.getDb();
 
diff --git a/src/mongo/db/curop.cpp b/src/mongo/db/curop.cpp
index b95b61b83fc..9d26d1c206c 100644
--- a/src/mongo/db/curop.cpp
+++ b/src/mongo/db/curop.cpp
@@ -443,6 +443,9 @@ bool CurOp::completeAndLogOperation(OperationContext* opCtx,
             // We can get here and our lock acquisition be timed out or interrupted, log a
             // message if that happens.
             try {
+                // Retrieving storage stats should not be blocked by oplog application.
+                ShouldNotConflictWithSecondaryBatchApplicationBlock shouldNotConflictBlock(
+                    opCtx->lockState());
                 Lock::GlobalLock lk(opCtx,
                                     MODE_IS,
                                     Date_t::now() + Milliseconds(500),