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Draconar
Draconar

Reputation: 1195

How can I use Mongo $index so the query would NOT use any index

this question is somewhat strange, but I bumped onto it in a current implementation of mine:

I want to privilege inserts over everything in my application and it came to my mind that the command $hint could also be used to let mongo NOT use an index.

Is that possible? is that a sound question, considering what $hint is supposed to do?

Thanks

Upvotes: 1

Views: 2414

Answers (2)

Sammaye
Sammaye

Reputation: 43884

I don't think inserts work the way you think.

An insert will catalogue it's needed fields to the btree dependant upon the number of indexes on the collection itself. As such to privilege inserts you would have to destroy all indexes on the collection.

As such using $natural order hinting will make no difference to the order of read and write. Not to mention $natural order is a disk insertion index, just an index you cannot effectively use in a query as such it will force full table scan.

However that does not actually privilege anything since maintaining the btree is part of inserting data so as such there is no way, via indexes to prioritise inserts.

Also the write and read lock are two completely different things so again I am not sure if your question makes sense.

Are you more like looking for an atomic lock to ensure that you update or put data in before it is read?

Upvotes: 5

Thilo
Thilo

Reputation: 262534

To force the query optimizer to not use indexes (do a table scan), use:

db.collection.find().hint({$natural:1})

Not sure if this achieves what you want (prioritizing inserts over other activity), though.

Upvotes: 6

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