Merge pull request #333 from magento-fearless-kiwis/MAGETWO-55589-bat…

…ch-size

Fixed issues:
 - MAGETWO-55589: Wrong algorithm for calculation batch size on category indexing

lib/internal/Magento/Framework/DB/Adapter/Pdo/Mysql.php

@@ -26,6 +26,7 @@
 use Magento\Framework\Phrase;
 use Magento\Framework\Stdlib\DateTime;
 use Magento\Framework\Stdlib\StringUtils;
+use Magento\Framework\DB\Query\Generator as QueryGenerator;
 
 /**
  * @SuppressWarnings(PHPMD.ExcessivePublicCount)
@@ -199,6 +200,11 @@ class Mysql extends \Zend_Db_Adapter_Pdo_Mysql implements AdapterInterface
      */
     private $exceptionMap;
 
+    /**
+     * @var QueryGenerator
+     */
+    private $queryGenerator;
+
     /**
      * @param StringUtils $string
      * @param DateTime $dateTime
@@ -3362,57 +3368,32 @@ public function insertFromSelect(Select $select, $table, array $fields = [], $mo
      * @param int $stepCount
      * @return \Magento\Framework\DB\Select[]
      * @throws LocalizedException
+     * @deprecated
      */
     public function selectsByRange($rangeField, \Magento\Framework\DB\Select $select, $stepCount = 100)
     {
-        $fromSelect = $select->getPart(\Magento\Framework\DB\Select::FROM);
-        if (empty($fromSelect)) {
-            throw new LocalizedException(
-                new \Magento\Framework\Phrase('Select object must have correct "FROM" part')
-            );
-        }
-
-        $tableName = [];
-        $correlationName = '';
-        foreach ($fromSelect as $correlationName => $formPart) {
-            if ($formPart['joinType'] == \Magento\Framework\DB\Select::FROM) {
-                $tableName = $formPart['tableName'];
-                break;
-            }
-        }
-
-        $selectRange = $this->select()
-            ->from(
-                $tableName,
-                [
-                    new \Zend_Db_Expr('MIN(' . $this->quoteIdentifier($rangeField) . ') AS min'),
-                    new \Zend_Db_Expr('MAX(' . $this->quoteIdentifier($rangeField) . ') AS max'),
-                ]
-            );
-
-        $rangeResult = $this->fetchRow($selectRange);
-        $min = $rangeResult['min'];
-        $max = $rangeResult['max'];
-
+        $iterator = $this->getQueryGenerator()->generate($rangeField, $select, $stepCount);
         $queries = [];
-        while ($min <= $max) {
-            $partialSelect = clone $select;
-            $partialSelect->where(
-                $this->quoteIdentifier($correlationName) . '.'
-                . $this->quoteIdentifier($rangeField) . ' >= ?',
-                $min
-            )
-                ->where(
-                    $this->quoteIdentifier($correlationName) . '.'
-                    . $this->quoteIdentifier($rangeField) . ' < ?',
-                    $min + $stepCount
-                );
-            $queries[] = $partialSelect;
-            $min += $stepCount;
+        foreach ($iterator as $query) {
+            $queries[] = $query;
         }
         return $queries;
     }
 
+    /**
+     * Get query generator
+     *
+     * @return QueryGenerator
+     * @deprecated
+     */
+    private function getQueryGenerator()
+    {
+        if ($this->queryGenerator === null) {
+            $this->queryGenerator = \Magento\Framework\App\ObjectManager::getInstance()->create(QueryGenerator::class);
+        }
+        return $this->queryGenerator;
+    }
+
     /**
      * Get update table query using select object for join and update
      *

lib/internal/Magento/Framework/DB/Query/BatchIterator.php

@@ -0,0 +1,192 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Framework\DB\Query;
+
+use Magento\Framework\DB\Adapter\AdapterInterface;
+use Magento\Framework\DB\Select;
+
+/**
+ * Query batch iterator
+ */
+class BatchIterator implements \Iterator
+{
+    /**
+     * @var int
+     */
+    private $batchSize;
+
+    /**
+     * @var Select
+     */
+    private $select;
+
+    /**
+     * @var int
+     */
+    private $minValue = 0;
+
+    /**
+     * @var string
+     */
+    private $correlationName;
+
+    /**
+     * @var string
+     */
+    private $rangeField;
+
+    /**
+     * @var Select
+     */
+    private $currentSelect;
+
+    /**
+     * @var AdapterInterface
+     */
+    private $connection;
+
+    /**
+     * @var int
+     */
+    private $iteration = 0;
+
+    /**
+     * @var string
+     */
+    private $rangeFieldAlias;
+
+    /**
+     * @var bool
+     */
+    private $isValid = true;
+
+    /**
+     * Initialize dependencies.
+     *
+     * @param Select $select
+     * @param int $batchSize
+     * @param string $correlationName
+     * @param string $rangeField
+     * @param string $rangeFieldAlias
+     */
+    public function __construct(
+        Select $select,
+        $batchSize,
+        $correlationName,
+        $rangeField,
+        $rangeFieldAlias
+    ) {
+        $this->batchSize = $batchSize;
+        $this->select = $select;
+        $this->correlationName = $correlationName;
+        $this->rangeField = $rangeField;
+        $this->rangeFieldAlias = $rangeFieldAlias;
+        $this->connection = $select->getConnection();
+    }
+
+    /**
+     * @return Select
+     */
+    public function current()
+    {
+        if (null == $this->currentSelect) {
+            $this->currentSelect = $this->initSelectObject();
+            $itemsCount = $this->calculateBatchSize($this->currentSelect);
+            $this->isValid = $itemsCount > 0;
+        }
+        return $this->currentSelect;
+    }
+
+    /**
+     * @return Select
+     */
+    public function next()
+    {
+        if (null == $this->currentSelect) {
+            $this->current();
+        }
+        $select = $this->initSelectObject();
+        $itemsCountInSelect = $this->calculateBatchSize($select);
+        $this->isValid = $itemsCountInSelect > 0;
+        if ($this->isValid) {
+            $this->iteration++;
+            $this->currentSelect = $select;
+        } else {
+            $this->currentSelect = null;
+        }
+        return $this->currentSelect;
+    }
+
+    /**
+     * @return int
+     */
+    public function key()
+    {
+        return $this->iteration;
+    }
+
+    /**
+     * @return bool
+     */
+    public function valid()
+    {
+        return $this->isValid;
+    }
+
+    /**
+     * @return void
+     */
+    public function rewind()
+    {
+        $this->minValue = 0;
+        $this->currentSelect = null;
+        $this->iteration = 0;
+        $this->isValid = true;
+    }
+
+    /**
+     * Calculate batch size for select.
+     *
+     * @param Select $select
+     * @return int
+     */
+    private function calculateBatchSize(Select $select)
+    {
+        $wrapperSelect = $this->connection->select();
+        $wrapperSelect->from(
+            $select,
+            [
+                new \Zend_Db_Expr('MAX(' . $this->rangeFieldAlias . ') as max'),
+                new \Zend_Db_Expr('COUNT(*) as cnt')
+            ]
+        );
+        $row = $this->connection->fetchRow($wrapperSelect);
+        $this->minValue = $row['max'];
+        return intval($row['cnt']);
+    }
+
+    /**
+     * Initialize select object.
+     *
+     * @return \Magento\Framework\DB\Select
+     */
+    private function initSelectObject()
+    {
+        $object = clone $this->select;
+        $object->where(
+            $this->connection->quoteIdentifier($this->correlationName)
+            . '.' . $this->connection->quoteIdentifier($this->rangeField)
+            . ' > ?',
+            $this->minValue
+        );
+        $object->limit($this->batchSize);
+        /**
+         * Reset sort order section from origin select object
+         */
+        $object->order($this->correlationName . '.' . $this->rangeField . ' ' . \Magento\Framework\DB\Select::SQL_ASC);
+        return $object;
+    }
+}

lib/internal/Magento/Framework/DB/Query/BatchIteratorFactory.php

@@ -0,0 +1,51 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Framework\DB\Query;
+
+/**
+ * Factory class for @see \Magento\Framework\DB\Query\BatchIterator
+ */
+class BatchIteratorFactory
+{
+    /**
+     * Object Manager instance
+     *
+     * @var \Magento\Framework\ObjectManagerInterface
+     */
+    private $objectManager = null;
+
+    /**
+     * Instance name to create
+     *
+     * @var string
+     */
+    private $instanceName = null;
+
+    /**
+     * Factory constructor
+     *
+     * @param \Magento\Framework\ObjectManagerInterface $objectManager
+     * @param string $instanceName
+     */
+    public function __construct(
+        \Magento\Framework\ObjectManagerInterface $objectManager,
+        $instanceName = \Magento\Framework\DB\Query\BatchIterator::class
+    ) {
+        $this->objectManager = $objectManager;
+        $this->instanceName = $instanceName;
+    }
+
+    /**
+     * Create class instance with specified parameters
+     *
+     * @param array $data
+     * @return \Magento\Framework\DB\Query\BatchIterator
+     */
+    public function create(array $data = [])
+    {
+        return $this->objectManager->create($this->instanceName, $data);
+    }
+}