MAGETWO-64187: Batch size algorithm

Author: Stanislav Idolov

app/code/Magento/Catalog/Model/ResourceModel/Product/Indexer/Price/BatchSizeCalculator.php

@@ -6,6 +6,9 @@
 
 namespace Magento\Catalog\Model\ResourceModel\Product\Indexer\Price;
 
+/**
+ * Ensure that size of index MEMORY table is enough for configured rows count in batch.
+ */
 class BatchSizeCalculator
 {
     /**

app/code/Magento/Catalog/Model/ResourceModel/Product/Indexer/Price/CompositeProductRowSizeEstimator.php

@@ -8,6 +8,9 @@
 
 use Magento\Framework\Indexer\IndexTableRowSizeEstimatorInterface;
 
+/**
+ * Estimate index memory size for largest composite product in catalog.
+ */
 class CompositeProductRowSizeEstimator implements IndexTableRowSizeEstimatorInterface
 {
     /**

app/code/Magento/Catalog/Model/ResourceModel/Product/Indexer/Price/IndexTableRowSizeEstimator.php

@@ -6,6 +6,10 @@
 
 namespace Magento\Catalog\Model\ResourceModel\Product\Indexer\Price;
 
+/**
+ * Estimate index memory size for simple product.
+ * Size depends on websites and customer groups count.
+ */
 class IndexTableRowSizeEstimator implements \Magento\Framework\Indexer\IndexTableRowSizeEstimatorInterface
 {
     /**

lib/internal/Magento/Framework/Indexer/BatchSizeManagement.php

@@ -6,6 +6,9 @@
 
 namespace Magento\Framework\Indexer;
 
+/**
+ * Class set MEMORY table size for indexer processes according batch size and index row size.
+ */
 class BatchSizeManagement implements \Magento\Framework\Indexer\BatchSizeManagementInterface
 {
     /**
@@ -28,14 +31,13 @@ public function __construct(
      */
     public function ensureBatchSize(\Magento\Framework\DB\Adapter\AdapterInterface $connection, $batchSize)
     {
-        // Calculate memory table size for product
-        $memoryForLargeComposite = $this->rowSizeEstimator->estimateRowSize();
+        $rowMemory = $this->rowSizeEstimator->estimateRowSize();
 
         $maxHeapTableSize = $connection->fetchOne('SELECT @@max_heap_table_size;');
         $tmpTableSize = $connection->fetchOne('SELECT @@tmp_table_size;');
         $maxMemoryTableSize = min($maxHeapTableSize, $tmpTableSize);
 
-        $size = (int) ($memoryForLargeComposite * $batchSize);
+        $size = (int) ($rowMemory * $batchSize);
 
         if ($maxMemoryTableSize < $size) {
             $connection->query('SET SESSION tmp_table_size = ' . $size . ';');

lib/internal/Magento/Framework/Indexer/BatchSizeManagementInterface.php

@@ -9,6 +9,7 @@
 
 /**
  * Batch size manager can be used to ensure that MEMORY table has enough memory for data in batch.
+ * @api
  */
 interface BatchSizeManagementInterface
 {

lib/internal/Magento/Framework/Indexer/IndexTableRowSizeEstimatorInterface.php

@@ -6,10 +6,14 @@
 
 namespace Magento\Framework\Indexer;
 
+/**
+ * Calculate memory size for entity according different dimensions.
+ * @api
+ */
 interface IndexTableRowSizeEstimatorInterface
 {
     /**
-     * Calculate memory size for product row.
+     * Calculate memory size for entity row.
      *
      * @return float
      */