Resulting document after update is larger than 16777216

依赖包是

问题原因：

更新文档后data的数据量太大了，超过了16M。

解决办法：

1、优化自己的mongo代码逻辑，取消文档中的集合存储已文档的方式存储

2、修改mongo的源码，改变源代码并从源代码构建自己的mongo版本。

/* Note the limit here is rather arbitrary and is simply a standard. generally the code works
   with any object that fits in ram.
   Also note that the server has some basic checks to enforce this limit but those checks are not exhaustive
   for example need to check for size too big after
     update $push (append) operation
     various db.eval() type operations
*/
const int BSONObjMaxUserSize = 16 * 1024 * 1024;

/*
   Sometimes we need objects slightly larger - an object in the replication local.oplog
   is slightly larger than a user object for example.
*/
const int BSONObjMaxInternalSize = BSONObjMaxUserSize + ( 16 * 1024 );

const int BufferMaxSize = 64 * 1024 * 1024;

参考mongo/builder.h at 4211c6a8de32fa774b1c28fb82a96f965fd550b7 · mongodb/mongo · GitHub