Problem:
Slow MongoDB subscription inside Meteor (on average 500ms), CPU usage stays at 100% after starting meteor. I suspect it is a permission or settings issue.
Details:
1) Setup: CentOS 6.6, MongoDB 3.0 with Oplog tailing enabled, fast CPU, lots of RAM. Complication, any command beginning with SUDO incurrs 10-30s delay.
2) Serverside publication:
Meteor.publish('price', function() {
return priceCollection.find({"type":"Price","Name":"item1"}, {sort: {"date": -1}, fields:{"type": 1, "Name": 1, "date": 1, "value": 1}, limit: 2});
});
3) Clientside subscription via Iron Router using Subscription Manager
waitOn: function() {
return [permanentSubs.subscribe("price")];
}
4) Remote MongoDB performance:
rs0:PRIMARY> db.priceCollection.find({"type":"Price", "Name":"item1"}, {"type":1, "Name":1, "date":1, "value":1}).sort({"date":-1}).limit(2).explain("executionStats")
The proper index is used and execution time is on average between 0-10ms.
5) Meteor Minimongo performance: no performance issues after subscription is done, 2 documents return without any delay using Chrome browser console.
6) Need to wait for one second before page renders. Using Kadira shows publication time ranges between 400ms-600ms.
7) Running Kadira CPU profiler: 53% package:ejson, 25% package:underscore, the rest: <1%.
8) Kadira shows no server side errors and subscription errors.
Want answers to
1) Where to begin hunting down the root cause of the slow down?
2) Is there any other debugging tools available to breakdown subscription process to help debug subscription performance issue.
If more information is required, please leave comments.