text: var maxBsonObjectSize = db.isMaster().maxBsonObjectSize;
  var docOverhead = Object.bsonsize({_id: new ObjectId(), x: ''});
  var maxStrSize = maxBsonObjectSize - docOverhead;
  var maxStr = 'a'.repeat(maxStrSize);
  var coll = db.max_doc_size;
  
  coll.drop();
  var res = db.runCommand({insert: coll.getName(), documents: [{_id: new ObjectId(), x: maxStr}]});
  assert(res.ok);
  assert.eq(null, res.writeErrors);
  
  coll.drop();
  res = db.runCommand({
      update: coll.getName(),
      ordered: true,
      updates: [{q: {a: 1}, u: {_id: new ObjectId(), x: maxStr}, upsert: true}]
  });
  assert(res.ok);
  assert.eq(null, res.writeErrors);
  
  coll.drop();
  var id = new ObjectId();
  coll.insert({_id: id});
  res = db.runCommand(
      {update: coll.getName(), ordered: true, updates: [{q: {_id: id}, u: {$set: {x: maxStr}}}]});
  assert(res.ok);
  assert.eq(null, res.writeErrors);
  
  //
  // Test documents over the size limit.
  //
  
  var overBigStr = maxStr + 'a';
  
  coll.drop();
  res = db.runCommand({insert: coll.getName(), documents: [{_id: new ObjectId(), x: overBigStr}]});
  assert(res.ok);
  assert.neq(null, res.writeErrors);
  
  coll.drop();
  res = db.runCommand({
      update: coll.getName(),
      ordered: true,
      updates: [{q: {a: 1}, u: {_id: new ObjectId(), x: overBigStr}, upsert: true}]
  });
  assert(res.ok);
  assert.neq(null, res.writeErrors);
  
  coll.drop();
  id = new ObjectId();
  coll.insert({_id: id});
  res = db.runCommand(
      {update: coll.getName(), ordered: true, updates: [{q: {_id: id}, u: {$set: {x: overBigStr}}}]});
  assert(res.ok);
  assert.neq(null, res.writeErrors);
  