1 files changed, 55 insertions, 0 deletions
diff --git a/jstests/noPassthrough/metadata_size_estimate.js b/jstests/noPassthrough/metadata_size_estimate.js
new file mode 100644
index 00000000000..55e224d2487
--- /dev/null
+++ b/jstests/noPassthrough/metadata_size_estimate.js
@@ -0,0 +1,55 @@
+// Test the impact of having too many roles
+// @tags: [requires_sharding]
+
+(function() {
+'use strict';
+
+// Use a relatively small record size to more reliably hit a tipping point where the write batching
+// logic thinks we have more space available for metadata than we really do.
+const kDataBlockSize = 64 * 1024;
+const kDataBlock = 'x'.repeat(kDataBlockSize);
+const kBSONMaxObjSize = 16 * 1024 * 1024;
+const kNumRows = (kBSONMaxObjSize / kDataBlockSize) + 5;
+
+function runTest(conn) {
+    const admin = conn.getDB('admin');
+    assert.commandWorked(admin.runCommand({createUser: 'admin', pwd: 'pwd', roles: ['root']}));
+    assert(admin.auth('admin', 'pwd'));
+
+    // Create more than 16KB of role data.
+    // These roles are grouped into a meta-role to avoid calls to `usersInfo` unexpectedly
+    // overflowing from duplication of roles/inheritedRoles plus showPrivileges.
+    const userRoles = [];
+    for (let i = 0; i < 10000; ++i) {
+        userRoles.push({db: 'qwertyuiopasdfghjklzxcvbnm_' + i, role: 'read'});
+    }
+    assert.commandWorked(
+        admin.runCommand({createRole: 'bigRole', roles: userRoles, privileges: []}));
+    assert.commandWorked(admin.runCommand({createUser: 'user', pwd: 'pwd', roles: ['bigRole']}));
+    admin.logout();
+
+    assert(admin.auth('user', 'pwd'));
+    const db = conn.getDB(userRoles[0].db);
+
+    // Fill a collection with enough rows to necessitate paging.
+    for (let i = 1; i <= kNumRows; ++i) {
+        assert.commandWorked(db.myColl.insert({_id: i, data: kDataBlock}));
+    }
+    // Verify initial write.
+    assert.eq(kNumRows, db.myColl.count({}));
+
+    // Create an aggregation which will batch up to kMaxWriteBatchSize or 16MB
+    // (not counting metadata)
+    assert.eq(0, db.myColl.aggregate([{"$out": 'yourColl'}]).itcount(), 'Aggregation failed');
+
+    // Verify the $out stage completed.
+    assert.eq(db.myColl.count({}), db.yourColl.count({}));
+    assert.eq(kNumRows, db.yourColl.count({}));
+}
+
+{
+    const st = new ShardingTest({mongos: 1, config: 1, shards: 1});
+    runTest(st.s0);
+    st.stop();
+}
+})();