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cursor.snapshot()

cursor.snapshot()

Append the snapshot() method to a cursor to toggle the “snapshot” mode. This ensures that the query will not return a document multiple times, even if intervening write operations result in a move of the document due to the growth in document size.

警告

  • You must apply snapshot() to the cursor before retrieving any documents from the database.
  • You can only use snapshot() with unsharded collections.

The snapshot() does not guarantee isolation from insertion or deletions.

The snapshot() traverses the index on the _id field. As such, snapshot() cannot be used with sort() or hint().

Queries with results of less than 1 megabyte are effectively implicitly snapshotted.

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