Set writeConcern level to unacknowledged in pymongo

Question

I have a huge mongodb database and due to the fact that only one thread is writing in a collection at any given time and all the updates are performed on documents that already exist, I'd like mongodb to not acknowledge any operation because I want to boost performance.

I came across a writeConcern rundown here but I have no idea how apply use the unacknowledged write concern on updates in pymongo.

Note: I'm using pymongo 2.7.1, python 3.4 and mongo 2.6.3

Edit: I'd like to add the bulk version of modified write concern update to Neil Lunn's solution.

Answer 1

You can do this in either one of two places.

1. Either when obtaining the initial MongoClient:

   client = MongoClient(w=0)
   

2. Or when issuing statements as an additional argument:

   result = db.collection.update({ 'a': 1 }, { 'a': 2 }, w=0 )
   

Both are valid places to specify a write concern. What you specify on MongoClient is "global" for the connection and the other statements override where used or otherwise just use the "global".