mongodb - mongo 3 duplicates on unique index - dropDups -

in documentation mongodb says: "changed in version 3.0: dropdups option no longer available."

is there can (other downgrading) if want create unique index , destroy duplicate entries?

please keep in mind receive 300 inserts per second can't delete duplicates , hope none come in time i'm done indexing.

yes dropdupes deprecated since version 2.7.5 because not possible predict correctly document deleted in process.

typically, have 2 options :

1. use new collection :

   • create new collection,
   • create unique index on new collection,
   • run batch copy documents old collection new 1 , make sure ignore duplicated key error during process.

2. deal in own collection manually :

   • make sure won't insert more duplicated documents in code,
   • run batch on collection delete duplicates (and make sure keep 1 if not identical),
   • then add unique index.

for particular case, recommend first option trick :

• create new collection unique index,
• update code insert documents in both tables,
• run batch copy documents old collection new 1 (ignore duplicated key error),
• rename new collection match old name.
• re-update code write in "old" collection