check existing via a map instead of a lodash.find

lib/dialects/abstract/query.js

@@ -350,14 +350,8 @@ module.exports = (function() {
         })
         delete result.__children
       },
-      primaryKeyAttribute
-
-    // Identify singular primaryKey attribute for equality check (if possible)
-    if (includeOptions.daoFactory.primaryKeyAttributes.length === 1) {
-      primaryKeyAttribute = includeOptions.daoFactory.primaryKeyAttributes[0]
-    } else if (includeOptions.daoFactory.rawAttributes.id) {
-      primaryKeyAttribute = 'id'
-    }
+      primaryKeyAttribute = includeOptions.daoFactory.primaryKeyAttribute,
+      primaryKeyMap = {}
 
     // Ignore all include keys on main data
     if (includeOptions.includeNames) {
@@ -369,18 +363,23 @@ module.exports = (function() {
       calleeData = _.omit(row, calleeDataIgnore)
 
       // If there are :M associations included we need to see if the main result of the row has already been identified
-      existingResult = options.checkExisting && _.find(results, function (result) {
-        // If we can, detect equality on the singular primary key
+      if (options.checkExisting) {
         if (primaryKeyAttribute) {
-          return result[primaryKeyAttribute] === calleeData[primaryKeyAttribute]
+          // If we can, detect equality on the singular primary key
+          existingResult = primaryKeyMap[calleeData[primaryKeyAttribute]]
+        } else {
+          // If we can't identify on a singular primary key, do a full row equality check
+          existingResult = _.find(results, function (result) {
+            return Utils._.isEqual(_.omit(result, calleeDataIgnore), calleeData)
+          })
         }
-
-        // If we can't identify on a singular primary key, do a full row equality check
-        return Utils._.isEqual(_.omit(result, calleeDataIgnore), calleeData)
-      })
+      }
 
       if (!existingResult) {
         results.push(existingResult = calleeData)
+        if (primaryKeyAttribute) {
+          primaryKeyMap[existingResult[primaryKeyAttribute]] = existingResult
+        }
       }
 
       for (var attrName in row) {