Info
When a sharded query on a view with maxTimeMS is rewritten on mongos to a query over the view's backing collection, the maxTimeMS is discarded. The consequence is that the maxTimeMS is not enforced for a sharded queries over views. This is true for both views on sharded and unsharded collections. MaxTimeMS does work, however, for queries against a view delivered directly to mongod.
Top User Comments
xgen-internal-githook commented on Wed, 5 Apr 2017 17:51:44 +0000:
Author:
{u'username': u'jameswahlin', u'name': u'James Wahlin', u'email': u'james.wahlin@10gen.com'}
Message: SERVER-28040 Fix maxTimeMS/readPref/readConcern for sharded view query
Branch: master
https://github.com/mongodb/mongo/commit/c3341d179db1c36722284676d99cb1c664fb1821
Steps to Reproduce
Start a one-shard cluster, then run the following against the mongos:
db.c.drop();
var padding = new Array(12000000).toString();
for (var j=0; j < 100; ++j) {
db.c.insert({x: padding})
}
db.createView("view", "c", []);
// As expected, this errors with ExceededTimeLimit.
db.c.find().maxTimeMS(1).itcount();
// This operation is expected to time out, but instead it succeeds (and takes much longer than 1 millisecond).
db.view.find().maxTimeMS(1).itcount();
