问题
I'm creating a index in mongo:
db.table.createIndex({"chr" : 1, "Start" : 1, "End" : 1, "Ref" : 1, "Alt" : 1})
It runs for some time and gives an error msg:
error in monogdb "errmsg" : "WiredTigerIndex::insert: key too large to index, failing
How do I fix this error?
回答1:
In MongoDB, since 2.6, the total size of an index entry must be less than 1024 bytes. Documentation here
In other terms, at least one of your documents has a large value in one of the field you are trying to index.
It's not a good idea in general to index very large values like that because it creates a big index which is less efficient compared to a smaller one and it takes more space in RAM which could be put to better use on a MongoDB node.
You could use this : mongod --setParameter failIndexKeyTooLong=false.
But it doesn't look like a good idea. If you have a large text to index, you should consider using the Full Text index or you could use a Hashed index.
回答2:
This can also be caused by having both a text index and a standard index for the same field. By deleting one of them you will be able to resolve this issue.
来源：https://stackoverflow.com/questions/43342082/error-in-monogdb-errmsg-wiredtigerindexinsert-key-too-large-to-index-fa