1 files changed, 45 insertions, 0 deletions
diff --git a/jstests/noPassthrough/max_conns_override.js b/jstests/noPassthrough/max_conns_override.js
new file mode 100644
index 00000000000..5fa28804856
--- /dev/null
+++ b/jstests/noPassthrough/max_conns_override.js
@@ -0,0 +1,45 @@
+(function() {
+    'use strict';
+    const configuredMaxConns = 5;
+    const configuredReadyAdminThreads = 3;
+    let conn = MongoRunner.runMongod({
+        config: "jstests/noPassthrough/libs/max_conns_override_config.yaml",
+        // We check a specific field in this executor's serverStatus section
+        serviceExecutor: "synchronous",
+    });
+
+    // Use up all the maxConns with junk connections, all of these should succeed
+    let maxConns = [];
+    for (let i = 0; i < 5; i++) {
+        maxConns.push(new Mongo(`127.0.0.1:${conn.port}`));
+        let tmpDb = maxConns[maxConns.length - 1].getDB("admin");
+        assert.commandWorked(tmpDb.runCommand({isMaster: 1}));
+    }
+
+    // Get serverStatus to check that we have the right number of threads in the right places
+    let status = conn.getDB("admin").runCommand({serverStatus: 1});
+    const connectionsStatus = status["connections"];
+    const reservedExecutorStatus = connectionsStatus["adminConnections"];
+    const normalExecutorStatus = status["network"]["serviceExecutorTaskStats"];
+
+    // Log these serverStatus sections so we can debug this easily
+    print("connections status section: ", tojson(connectionsStatus));
+    print("normal executor status section: ", tojson(normalExecutorStatus));
+
+    // The number of "available" connections should be less than zero, because we've used
+    // all of maxConns. We're over the limit!
+    assert.lt(connectionsStatus["available"], 0);
+    // The number of "current" connections should be greater than maxConns
+    assert.gt(connectionsStatus["current"], configuredMaxConns);
+    // The number of ready threads should be the number of readyThreads we configured, since
+    // every thread spawns a new thread on startup
+    assert.eq(reservedExecutorStatus["readyThreads"] + reservedExecutorStatus["startingThreads"],
+              configuredReadyAdminThreads);
+    // The number of running admin threads should be greater than the readyThreads, because
+    // one is being used right now
+    assert.gt(reservedExecutorStatus["threadsRunning"], reservedExecutorStatus["readyThreads"]);
+    // The normal serviceExecutor should only be running maxConns number of threads
+    assert.eq(normalExecutorStatus["threadsRunning"], configuredMaxConns);
+
+    MongoRunner.stopMongod(conn);
+})();