mongodb - How to update a single field in a capped collection in MongoDB?

Question

db.events.update(
   {upload:0},
   {$set:{upload:1}},
   {multi:true}
)

I am getting the following error even though I am just replacing an integer with another integer.

Cannot change the size of a document in a capped collection: 402 != 406

Answer 1

看起来您插入的是 adouble而不是int32(double比 宽 4 个字节int32)。

来自mongodb 类型文档：

整数

默认情况下，mongo shell 将所有数字视为浮点值。mongo shell 提供 NumberInt() 构造函数来显式指定 32 位整数。

要解决此问题，只需将您的代码更改为：

 db.events.update(
   {upload:0},
   {$set:{upload: NumberInt(1)}},
   {multi:true}
)