title: MongoDB Aggregation V/S simple query performance?
body: <p>I am reasking this question as i thought this question should be on seperate thread from  this one <a href="https://stackoverflow.com/questions/41090280/in-mongodb-know-index-of-array-element-matched-with-in-operator/41109639">in-mongodb-know-index-of-array-element-matched-with-in-operator</a>.</p>
  
  <p>I am using mongoDB and actually i was writing all of my queries using simple queries which are find, update etc. (No Aggregations). Now i read on many SO posts see this one for example <a href="https://stackoverflow.com/questions/28364319/mongodb-aggregation-match-vs-find-speed">mongodb-aggregation-match-vs-find-speed</a>. Now i thought about why increasing computation time on server because as if i will compute more then my server load will become more, so i tried to use aggregations and i thought i am going in right direction now. But later on my previous question <a href="https://stackoverflow.com/users/3124885/andreas-limoli">andreas-limoli</a> told me about not using aggregations as it is slow and for using simple queries and computing on server. Now literally i am in a delimma about what should i use, i am working with mongoDB from a year now but i don't have any knowledge about its performance when data size increases so i completely don't know which one should i pick. </p>
  
  <p>Also one more thing i didn't find on anywhere, if aggregation is slower than is it because of $lookup or not, because $lookup is the foremost thing i thought about using aggregation because otherwise i have to execute many queries serially and then compute on server which appears to me very poor in front of aggregation.</p>
  
  <p>Also i read about 100MB restriction on mongodb aggregation when passing data from one pipeline to other, so how people handle that case efficiently and also if they turn on Disk usage then because Disk usage slow down everything than how people handle that case.</p>
  
  <p>Also i fetched 30,000 sample collection and tried to run aggregation with $match and find query and i found that aggregation was little bit faster than find query which was aggregation took 180ms to execute where as find took 220 ms to execute.</p>
  
  <p>Please help me out guys please it would be really helpful for me.</p>