CODEWITHSUNDEEP
mongodbmongodb-query
user6790571
user6790571

Reputation: 141

What is difference between "size" and "storageSize" displayed by Mongo stats() function

What is difference between "size" and "storageSize" displayed by Mongo stats() function? Which one shows the actual size on disk for a particular collection? Refer sample data returned by command

db.getCollection('temp_collection').stats()


{"ns" : "DB1.temp_collection",
    "count" : 1035219,
    "size" : 1186,
    "avgObjSize" : 1202,
    "storageSize" : 177,
    "capped" : false,
    "wiredTiger" : 
}

Upvotes: 14

Views: 10278

Answers (1)

profesor79
profesor79

Reputation: 9473

in simple words:

  • size refers for logical allocation (this is seen by database engine)
  • storageSize refers for physical file space allocation

As WT (WiredTiger) is used, with enabled data compression, then physical allocation is smaller because of compression

db.collection.storageSize

db.collection.stats

Upvotes: 19

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