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

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