Meteor's subscription and sync are slow

Question

I have a collection with 10M documents of 6000 stocks, stock name is indexed. When I subscribe to a new stock, meteor hangs more than 10 seconds to get about 3000 documents

Answer 1

I was struggling with the same issue. In my case I only had to sync ~3000 records, around 30KB total. After weeks of trying I eventually realized that the sync was not the issue, but seemingly the LiveHTML updates that happened while syncing.

I was able to reduce my page load from 10 seconds for 300 (filtered) records to less than 2 seconds for all 3000 records by disabling template updates during the initial page load. I accomplished that by adding a condition to the function that defined the template content:

Before (10s page load for 300 records being published by the server):

Template.itemlist.items = function () {
    return Item.find({type: 'car'},
                     {sort: {start: -1},
                      limit: 30});
};

To (2s page load for 3000 records published by the server):

Template.itemlist.items = function () {
    if (Session.get("active")) {    
        return Item.find({type: 'car'},
                         {sort: {start: -1},
                          limit: 30});
    } else {
        return [];
    }
};

To "activate" the session only once the data was loaded, I added:

Deps.autorun(function () {
    Meteor.subscribe("Item", 
                     {
                         onReady: function() {
                             Session.set("active", true);
                         }
                     });
});