From 87784ffc89a40c852d7c567f788b5a209c23b3a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20H=C3=BCnig?= <jonas@huenig.name>
Date: Mon, 28 Jun 2021 23:29:52 +0200
Subject: [PATCH] backport showTableStatus from Magento2

At the moment, Magento2 has a special code path inside showTableStatus() when MySQL8 is used.

This is needed, to flush information_schema_stats Cache introuded in MySQL 8.

As some modules, are using showTableStatus to recieve autoinvrement ID, this ones will break with MySQL 8 when  information_schema_stats_expiry  is > 0.

This PR will allow the use of showTableStatus without the need to disable status information_schema_stats Cache.
---
 lib/Varien/Db/Adapter/Pdo/Mysql.php | 37 +++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/lib/Varien/Db/Adapter/Pdo/Mysql.php b/lib/Varien/Db/Adapter/Pdo/Mysql.php
index 5a5ae13dff7..109b1ad13bf 100644
--- a/lib/Varien/Db/Adapter/Pdo/Mysql.php
+++ b/lib/Varien/Db/Adapter/Pdo/Mysql.php
@@ -221,6 +221,14 @@ class Varien_Db_Adapter_Pdo_Mysql extends Zend_Db_Adapter_Pdo_Mysql implements V
      * @var array|null
      */
     protected $_queryHook = null;
+    
+    /**
+     * Save if mysql engine is 8 or not.
+     *
+     * @var bool
+     */
+    private $isMysql8Engine;
+
 
     /**
      * Begin new DB transaction for connection
@@ -1057,6 +1065,22 @@ public function modifyColumn($tableName, $columnName, $definition, $flushData =
 
         return $this;
     }
+    
+    /**
+     * Checks if the engine is mysql 8
+     *
+     * @return bool
+     */
+    private function isMysql8EngineUsed(): bool
+    {
+        if (!$this->isMysql8Engine) {
+            $version = $this->fetchPairs("SHOW variables LIKE 'version'")['version'];
+            $this->isMysql8Engine = (bool) preg_match('/^(8\.)/', $version);
+        }
+
+        return $this->isMysql8Engine;
+    }
+
 
     /**
      * Show table status
@@ -1071,9 +1095,18 @@ public function showTableStatus($tableName, $schemaName = null)
         if ($schemaName !== null) {
             $fromDbName = ' FROM ' . $this->quoteIdentifier($schemaName);
         }
-        $query = sprintf('SHOW TABLE STATUS%s LIKE %s', $fromDbName,  $this->quote($tableName));
+        $query = sprintf('SHOW TABLE STATUS%s LIKE %s', $fromDbName, $this->quote($tableName));
+        //checks which slq engine used
+        if (!$this->isMysql8EngineUsed()) {
+            //if it's not MySQl-8 we just fetch results
+            return $this->rawFetchRow($query);
+        }
+        // Run show table status query in different connection because DDL queries do it in transaction,
+        // and we don't have actual table statistic in this case
+        $connection = $this->_transactionLevel ? $this->createConnection() : $this;
+        $connection->query(sprintf('ANALYZE TABLE %s', $this->quoteIdentifier($tableName)));
 
-        return $this->raw_fetchRow($query);
+        return $connection->query($query)->fetch(\PDO::FETCH_ASSOC);
     }
 
     /**