CODEWITHSUNDEEP
mongodb
Amit Kathpal
Amit Kathpal

Reputation: 31

Remove obsolete collection in mongodb

I want to delete all the collections from my db which are not used for long time. Is there any why i can check when the particular collection was last used?

Upvotes: 0

Views: 92

Answers (1)

robjwilkins
robjwilkins

Reputation: 5652

It depends what you mean by 'last used'. If you mean the last time a document was inserted into the collection then you could do this by converting the ObjectId of the last inserted document into a date. The following query should return the date the last document was inserted:

db.<collection_name>.findOne({},{_id:1})._id.getTimestamp()

the findOne query will return documents in natural order, therefore if you input no query criteria ('{}') then it will return the most recently inserted document. You can then get the _id field and call the getTimestamp() function

I'm not sure if there is any way to reliably tell when a collection was last queried. If you're running your database with profiling enabled then there might be entries in the db.system.profile collection, or in the oplog.

Upvotes: 1

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