MAGETWO-92819: Optimize moveDataFromReplicaTableToReplicaTables

Author: duhon

app/code/Magento/Catalog/Model/Indexer/Product/Price/Action/Full.php

@@ -415,11 +415,17 @@ private function moveDataFromReplicaTableToReplicaTables(array $dimensions)
         if (!$dimensions) {
             return ;
         }
-        //TODO: need to update logic for run this move only when replica table is not empty
         $select = $this->dimensionTableMaintainer->getConnection()->select()->from(
-            $this->dimensionTableMaintainer->getMainReplicaTable([])
+             $mainReplicaTable = $this->dimensionTableMaintainer->getMainReplicaTable([])
         );
 
+        $check = clone $select;
+        $check->reset('columns')->columns('count(*)');
+
+        if (! $count = $this->dimensionTableMaintainer->getConnection()->query($check)->fetchColumn()) {
+            return;
+        }
+
         $replicaTablesByDimension = $this->dimensionTableMaintainer->getMainReplicaTable($dimensions);
 
         foreach ($dimensions as $dimension) {
@@ -439,6 +445,8 @@ private function moveDataFromReplicaTableToReplicaTables(array $dimensions)
                 \Magento\Framework\DB\Adapter\AdapterInterface::INSERT_ON_DUPLICATE
             )
         );
+
+        $this->_defaultIndexerResource->getConnection()->truncateTable($mainReplicaTable);
     }
 
     /**