In-Progress MongoDB Index Creation Remaining Time Estimation

estimate_remaining_time_for_index_creation_on_mongodb.js

// Quick, dirty, but useful.
// This script will estimate the rime remaining for any index building operations
// currently in course.
// You can either call it by passing a known index building operation opid to the
// estimate function or call estimateIndexOps() with no arguments, that will
// find all index building operations and estimate each one of them.
//
// Usage:
// estimateIndexOps();
// estimate(opid);

var estimate = function(opid) {
  var op = db.currentOp( { opid: opid })['inprog'][0];

  var time_taken = op["secs_running"];
  var message    = op["msg"];

  var state      = message.match(/(\d+)\/(\d+)/);
  var completed  = state[1];
  var total      = state[2];

  var completed_per_second = completed / time_taken;
  var time_to_complete_all = total / completed_per_second;
  var remaining_time       = time_to_complete_all - time_taken;

  print("->   " + message);
  print("     Namespace: " + op["insert"]["ns"]);
  print("     Index name: " + op["insert"]["name"] );
  print("     " + remaining_time.toFixed(0) + " remaining seconds, or")
  print("     " + remaining_time / (60*60) + ' hours, or');
  print("     " + remaining_time / 60 + ' minutes');

  return remaining_time;
}


function estimateIndexOps() {
  var active_index = db.currentOp(
      {
        $or: [
          { op: "query", "query.createIndexes": { $exists: true } },
          { op: "insert", ns: /\.system\.indexes\b/ }
        ]
      }
  );
  active_index["inprog"].forEach( function(op) {
    print("In progress index operation found: " + op['opid']);
    estimate(op['opid']);
    print("");
  });
}