db.getLastError() in mongoDB

getLastError(w?, wtimeout?)

This method specifies the level of write concern for confirming the success of a previous write operation issued over the same connection and returns the error string for that operation.

Note:

When using db.getLastError(), clients must issue the db.getLastError() on the same connection as the write operation they wish to confirm.

Syntax:

db.getLastError(w)

where w is any number.

Example 1: When the last error success.

MongoDB

db.getLastError(1)

Output:

null

Example 2: When lasterror failed

MongoDB

db.getLastError(2)

Output:

uncaught exception: Error: getlasterror failed: {
    "connectionId" : 1,
    "n" : 0,
    "badGLE" : {
            "getlasterror" : 1,
            "w" : 2
    },
    "ok" : 0,
    "errmsg" : "cannot use 'w' > 1 when a host is not replicated",
    "code" : 2,
    "codeName" : "BadValue"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
DB.prototype.getLastErrorObj@src/mongo/shell/db.js:706:15
DB.prototype.getLastError@src/mongo/shell/db.js:689:15