SERVER-112120 Check async oplog sampling does not block core operations (#42662)

Co-authored-by: Nic Hollingum <nic.hollingum@mongodb.com>
Co-authored-by: Gregory Wlodarek <gregory.wlodarek@mongodb.com>
GitOrigin-RevId: 947832b0bc0f33a729172a7d7e322e6145ee5000

jstests/noPassthrough/oplog/check_async_oplog_non_blocking.js

@@ -0,0 +1,107 @@
+/**
+ * Checks that, when async oplog sampling enabled, we aren't blocking any important operations.
+ *
+ * This test forces sampling to occur very slowly useSlowCollectionTruncateMarkerScanning: true. One
+ * oplog entry will be sampled per second. This means that we will sample at a minimum of 250
+ * seconds, since this is our initial oplog size. We test that ftdc, DML, DDL, TTL, oplog
+ * application operations are not affect by sampling ongoing asynchronously.
+
+ * @tags: [requires_replication, requires_persistence]
+ */
+import {ReplSetTest} from "jstests/libs/replsettest.js";
+import {TTLUtil} from "jstests/libs/ttl/ttl_util.js";
+
+function samplingIsIncomplete(primary) {
+    const status = primary.getDB("local").serverStatus();
+    assert.commandWorked(status);
+    jsTest.log.info(status.oplogTruncation);
+    return (!status.oplogTruncation.hasOwnProperty("processingMethod") ||
+            status.oplogTruncation.processingMethod == "in progress");
+}
+
+// Initialize a 2-node replica set with a slow oplog.
+const rst = new ReplSetTest({
+    nodes: 2,
+    nodeOptions: {
+        setParameter: {
+            "oplogSamplingAsyncEnabled": true,
+            ttlMonitorSleepSecs: 1,
+            useSlowCollectionTruncateMarkerScanning: true,
+        },
+    },
+});
+rst.startSet();
+rst.initiate();
+
+// Insert initial documents
+jsTest.log.info("Inserting initial set of documents into the collection.");
+let coll = rst.getPrimary().getDB("test").getCollection("yeehaw");
+for (let i = 0; i < 250; i++) {
+    assert.commandWorked(coll.insert({a: i}));
+}
+
+// Stop and restart the replica set
+rst.getPrimary().adminCommand({fsync: 1});
+rst.stopSet(null, true);
+jsTest.log.info("Replica set stopped for restart.");
+rst.startSet(null, true);
+jsTest.log.info("Replica set restarted.");
+
+const primary = rst.getPrimary();
+const primaryDb = primary.getDB("test");
+let secondary = rst.getSecondary();
+
+// Verify we're still sampling.
+assert(samplingIsIncomplete(primary));
+assert(samplingIsIncomplete(secondary));
+
+// Check sampling does not block oplog application
+{
+    for (let i = 0; i < 5; i++) {
+        assert.commandWorked(
+            rst.getPrimary().getDB("test").getCollection("sheep").insert({baa: i},
+                                                                         {writeConcern: {w: 2}}),
+        );
+    }
+    rst.awaitReplication();
+}
+
+// Check sampling does not block TTL
+{
+    assert.commandWorked(primaryDb.createCollection("cows"));
+    assert.commandWorked(
+        primaryDb.cows.createIndex({"lastModifiedDate": 1}, {expireAfterSeconds: 0}));
+
+    for (let i = 0; i < 5; i++) {
+        assert.commandWorked(
+            primaryDb.getCollection("cows").insert({"lastModifiedDate": new Date()}));
+    }
+
+    // TTL Monitor should now perform passes every second. A timeout here would mean we fail the
+    // test.
+    TTLUtil.waitForPass(primaryDb, true, 20 * 1000);
+
+    assert.eq(primaryDb.cows.count(), 0, "We should get 0 documents after TTL monitor run");
+}
+
+// Check sampling does not block any DML or DDL operations
+{
+    assert.commandWorked(primaryDb.createCollection("pigs"));
+
+    // Insert document
+    assert.commandWorked(primaryDb.pigs.insertOne({name: "oink", age: 5}));
+    // Update document
+    assert.commandWorked(primaryDb.pigs.updateOne({name: "oink"}, {$set: {age: 6}}));
+    // Count documents
+    assert.eq(primaryDb.pigs.countDocuments({age: {$gte: 3}}), 1);
+    // Delete document
+    assert.commandWorked(primaryDb.pigs.deleteOne({name: "oink"}));
+
+    assert(primaryDb.pigs.drop());
+}
+
+// Verify we're still sampling.
+assert(samplingIsIncomplete(primary));
+assert(samplingIsIncomplete(secondary));
+
+rst.stopSet();