Improve performance in cases where we have a single primary key

lib/dialects/abstract/query.js

@@ -230,7 +230,11 @@ module.exports = (function() {
 
     // Queries with include
     } else if (this.options.hasJoin === true) {
-      results = groupJoinData(results, this.options, {
+      results = groupJoinData(results, {
+        daoFactory: this.callee,
+        includeMap: this.options.includeMap,
+        includeNames: this.options.includeNames
+      }, {
         checkExisting: this.options.hasMultiAssociation
       })
 
@@ -338,7 +342,22 @@ module.exports = (function() {
       , calleeData
       , child
       , calleeDataIgnore = ['__children']
+      , parseChildren = function(result) {
+        _.each(result.__children, function (children, key) {
+          result[key] = groupJoinData(children, (includeOptions.includeMap && includeOptions.includeMap[key]), options)
+        })
+        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'
+    }
 
+    // Ignore all include keys on main data
     if (includeOptions.includeNames) {
       calleeDataIgnore = calleeDataIgnore.concat(includeOptions.includeNames)
     }
@@ -349,10 +368,13 @@ module.exports = (function() {
 
       // 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 (calleeDataIgnore) {
-          return Utils._.isEqual(_.omit(result, calleeDataIgnore), calleeData)
+        // If we can, detect equality on the singular primary key
+        if (primaryKeyAttribute) {
+          return result[primaryKeyAttribute] === calleeData[primaryKeyAttribute]
         }
-        return Utils._.isEqual(result, 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) {
@@ -377,14 +399,17 @@ module.exports = (function() {
           }
         }
       }
+
+      // parseChildren in same loop if no duplicate values are possible
+      if (!options.checkExisting) {
+        parseChildren(existingResult)
+      }
     })
     
-    results.forEach(function (result) {
-      _.each(result.__children, function (children, key) {
-        result[key] = groupJoinData(children, (includeOptions.includeMap && includeOptions.includeMap[key]), options)
-      })
-      delete result.__children
-    })
+    // parseChildren after row parsing if duplicate values are possible
+    if (options.checkExisting) {
+      results.forEach(parseChildren)
+    }
 
     return results
   }