What's the fastest way to copy a collection within the same database?

I want to copy a collection within the same database and give it a different name - basically take a snapshot.

What's the best way to do this? Is there a command, or do I have to copy each record in turn?

I'm aware of the cloneCollection command, but it seems to be for copying to another server only.

I'm also aware of mongoimport and mongoexport, but as I'm doing this via PHP I'd prefer not to make calls out to the shell.

Solution 1:

db.myoriginal.aggregate([ { $match: {} }, { $out: "mycopy" } ])

It is a lot faster than doing many inserts in a forEach loop.

Solution 2:

You have a few options, but the fastest is:

mongodump -d db -c sourcecollection 
mongorestore -d db -c targetcollection --dir=dump/<db>/<sourcecollection.bson>

or

mongoexport -d db -c sourcecollection | mongoimport -d db -c targetcollection --drop

or in php:

`mongoexport -d db -c sourcecollection | mongoimport -d db -c targetcollection --drop`;

after that you have

mongo db < script.js

where, as shown in the mongo docs, script.js contains something like:

db.myoriginal.find().forEach( function(x){db.mycopy.insert(x)} );

The slowest (by an order of magnitude or more) way to copy a collection will be to use the native php driver - simply because of moving information around. But you could issue the above mongo query if you absolutely want to avoid cli calls using the db execute function.