Remove BasicEntityPersister::$insertSql cache property

When the persister is extended to do a multi update, the caching is not
wanted. The impact is minimal as the CPU/time overhead per query is
much bigger and the prepared statement is not cached anyway.

Author: mvorisek

src/Persisters/Entity/BasicEntityPersister.php

@@ -168,14 +168,6 @@ class BasicEntityPersister implements EntityPersister
      */
     protected $quotedColumns = [];
 
-    /**
-     * The INSERT SQL statement used for entities handled by this persister.
-     * This SQL is only generated once per request, if at all.
-     *
-     * @var string|null
-     */
-    private $insertSql;
-
     /**
      * The quote strategy.
      *
@@ -1473,18 +1465,13 @@ protected function getSelectManyToManyJoinSQL(array $manyToMany)
      */
     public function getInsertSQL()
     {
-        if ($this->insertSql !== null) {
-            return $this->insertSql;
-        }
-
         $columns   = $this->getInsertColumnList();
         $tableName = $this->quoteStrategy->getTableName($this->class, $this->platform);
 
         if (empty($columns)) {
-            $identityColumn  = $this->quoteStrategy->getColumnName($this->class->identifier[0], $this->class, $this->platform);
-            $this->insertSql = $this->platform->getEmptyIdentityInsertSQL($tableName, $identityColumn);
+            $identityColumn = $this->quoteStrategy->getColumnName($this->class->identifier[0], $this->class, $this->platform);
 
-            return $this->insertSql;
+            return $this->platform->getEmptyIdentityInsertSQL($tableName, $identityColumn);
         }
 
         $values  = [];
@@ -1508,9 +1495,7 @@ public function getInsertSQL()
         $columns = implode(', ', $columns);
         $values  = implode(', ', $values);
 
-        $this->insertSql = sprintf('INSERT INTO %s (%s) VALUES (%s)', $tableName, $columns, $values);
-
-        return $this->insertSql;
+        return sprintf('INSERT INTO %s (%s) VALUES (%s)', $tableName, $columns, $values);
     }
 
     /**