Count records with GlideAggregate, not getRowCount()

getRowCount() runs the full query and loads the result set just to tell you its size. GlideAggregate asks the database to count, which stays fast as tables grow.

var RecordCounter = Class.create();
RecordCounter.prototype = {
  initialize: function () {},

  /** Total rows matching an encoded query. */
  count: function (table, encodedQuery) {
    var ga = new GlideAggregate(table);
    if (encodedQuery) ga.addEncodedQuery(encodedQuery);
    ga.addAggregate('COUNT');
    ga.query();
    return ga.next() ? parseInt(ga.getAggregate('COUNT'), 10) : 0;
  },

  /** { groupDisplayValue: count } for one field. */
  countBy: function (table, field, encodedQuery) {
    var result = {};
    var ga = new GlideAggregate(table);
    if (encodedQuery) ga.addEncodedQuery(encodedQuery);
    ga.addAggregate('COUNT');
    ga.groupBy(field);
    ga.query();
    while (ga.next()) {
      result[ga.getDisplayValue(field) || '(empty)'] = parseInt(ga.getAggregate('COUNT'), 10);
    }
    return result;
  },

  type: 'RecordCounter',
};

// Usage
// var c = new RecordCounter();
// gs.info(c.count('incident', 'active=true'));
// gs.info(JSON.stringify(c.countBy('incident', 'priority', 'active=true')));

How it works

• addAggregate('COUNT') turns the query into a SELECT COUNT(*) on the database.
• groupBy() returns one row per distinct value, each with its own count.
• getAggregate() returns a string, so convert it before doing maths.

Gotchas

• Use getDisplayValue(field) for reference and choice fields, otherwise you get sys_ids and raw values.
• Other aggregates (SUM, AVG, MIN, MAX) take a field name as the second argument.