why is meteor Tracker.autorun() detects mongodb changes with a delay, if the collection was modified outside of the meteor application -

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a scenario: in local meteor (v 1.2.1) development environment (webstorm), autopublish, , insecure enabled, have single mongodbdb (v 3.0.4) collection 'letters'. wish respond documents being added, removed, or modified in collection.

for purpose, have following autorun function:

template.diagram.rendered = function(){  tracker.autorun(function () {         letters.find({}).observe({             added: function(document) {                 console.log('a new document has been added');             },             changed: function(newdocument) {                 console.log('a document has been changed');             },             removed: function(document) {                 console.log('a document has been removed');             }         });     }) }

when new document added within same application, can see console messages right away (meteor latency compensation). however, when connect same mongodb database using external tool (robomongo), , add, change, or remove document within 'letters' collection - takes 6-10 seconds before change detected, , corresponding console message appears in browser. why take long, instead of being instantaneous?

once have question posted on meteor forums, pointed meteor blog post 2014, describes oplog tailing feature, , fact, on default in dev instance. made me realize, that, using mongo_url env variable dev application, forcing meteor app work mongodb instance, running on mac time, independently meteor development, and, such, considered "production" meteor app. once have switched app work ad-hock mongo connection / db, oplog tailing went effect, , started see immediate event propagation browser. thanks, @dburles meteor forums!


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