问题
I get the following error (dump MongoDB 3.2) (restore MongoDB 3.4):
Failed: ngivr-dev.ledgerhelpers: error creating indexes for ngivr-dev.ledgerhelpers: **createIndex error:** **The field 'safe' is not valid for an index specification.** Specification: **{ unique: true, name: "ledgerId_1", safe: null, ns: "ngivr-dev.ledgerhelpers", background: true, key: { ledgerId: 1 } }**
Looks like the safe index is null. But how can i use it with MongoDB 3.4? 3.2 is ok.
回答1:
safe=true is not an index specification.
In previous versions of MongoDB, lower than 3.4, extra indexes specifications can be added. Those were used by specific drivers.
In 3.4, mongodb added a validation on indexes specification:
Ensuring that the specified index options are valid. Previous versions ignored invalid options.
That's why you have this error. I am afraid you need to ensure that the index in your 3.2 version does not have invalid index specificaitons, and after that do the mongodump.
As kz_sergey says in his answer, you can mongorestore using --noIndexRestore, that should work fine.
回答2:
Why do you restore indexes? --noIndexRestore and create them again.
回答3:
In the spirit of Aymeric's comment, you can use this awk one-liner to replace the "safe" property in your .metadata.json files.
awk -i inplace '{gsub(",\"safe\":null", ""); print}' *.metadata.json
Run it in the directory of your MongoDB export. This approach allows you to keep the indexes, but drop the "safe" option.
回答4:
find . -type f -name "*.metadata.json" -exec sed -i 's/,"safe":null//g' {} \;
This works and you will keep your indexes! It find all files in the present location (.) then using the same process (exec) replace in file (sed -i) according to the following regex which is basically saying all occurrences of "safe":null with nothing.
Replace the "." argument with the path to the directory where your mongodb exports are stored.
来源：https://stackoverflow.com/questions/41036442/mongodb-dump-from-3-2-restore-with-3-4-error-index-safe-null