From 94dccc6a00e47f738b13bb901723272971d3bb37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20=C4=8Ciha=C5=99?= <michal@cihar.com>
Date: Mon, 8 Feb 2016 10:55:54 +0100
Subject: [PATCH] Remove MySQL version caching
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In my testing the session/cache access is slower than fetching single
value from MySQL and calculating the values.

Also the caching would need some logic for invalidation as the server
can be upgraded or configuration changed.

Fixes #11924

Signed-off-by: Michal Čihař <michal@cihar.com>
---
 libraries/DatabaseInterface.php  | 91 +++++++++-----------------------
 libraries/VersionInformation.php |  2 +-
 2 files changed, 25 insertions(+), 68 deletions(-)

diff --git a/libraries/DatabaseInterface.php b/libraries/DatabaseInterface.php
index 87ab7eb181..5f8c0b6a35 100644
--- a/libraries/DatabaseInterface.php
+++ b/libraries/DatabaseInterface.php
@@ -1417,80 +1417,37 @@ class DatabaseInterface
     public function postConnect($link)
     {
         if (! defined('PMA_MYSQL_INT_VERSION')) {
-            if (Util::cacheExists('PMA_MYSQL_INT_VERSION')) {
+            $version = $this->fetchSingleRow(
+                'SELECT @@version, @@version_comment',
+                'ASSOC',
+                $link
+            );
+
+            if ($version) {
+                $match = explode('.', $version['@@version']);
+                define('PMA_MYSQL_MAJOR_VERSION', (int)$match[0]);
                 define(
                     'PMA_MYSQL_INT_VERSION',
-                    Util::cacheGet('PMA_MYSQL_INT_VERSION')
-                );
-                define(
-                    'PMA_MYSQL_MAJOR_VERSION',
-                    Util::cacheGet('PMA_MYSQL_MAJOR_VERSION')
-                );
-                define(
-                    'PMA_MYSQL_STR_VERSION',
-                    Util::cacheGet('PMA_MYSQL_STR_VERSION')
+                    (int) sprintf(
+                        '%d%02d%02d', $match[0], $match[1], intval($match[2])
+                    )
                 );
+                define('PMA_MYSQL_STR_VERSION', $version['@@version']);
                 define(
                     'PMA_MYSQL_VERSION_COMMENT',
-                    Util::cacheGet('PMA_MYSQL_VERSION_COMMENT')
-                );
-                define(
-                    'PMA_MARIADB',
-                    Util::cacheGet('PMA_MARIADB')
+                    $version['@@version_comment']
                 );
             } else {
-                $version = $this->fetchSingleRow(
-                    'SELECT @@version, @@version_comment',
-                    'ASSOC',
-                    $link
-                );
-
-                if ($version) {
-                    $match = explode('.', $version['@@version']);
-                    define('PMA_MYSQL_MAJOR_VERSION', (int)$match[0]);
-                    define(
-                        'PMA_MYSQL_INT_VERSION',
-                        (int) sprintf(
-                            '%d%02d%02d', $match[0], $match[1], intval($match[2])
-                        )
-                    );
-                    define('PMA_MYSQL_STR_VERSION', $version['@@version']);
-                    define(
-                        'PMA_MYSQL_VERSION_COMMENT',
-                        $version['@@version_comment']
-                    );
-                } else {
-                    define('PMA_MYSQL_INT_VERSION', 50501);
-                    define('PMA_MYSQL_MAJOR_VERSION', 5);
-                    define('PMA_MYSQL_STR_VERSION', '5.05.01');
-                    define('PMA_MYSQL_VERSION_COMMENT', '');
-                }
-                Util::cacheSet(
-                    'PMA_MYSQL_INT_VERSION',
-                    PMA_MYSQL_INT_VERSION
-                );
-                Util::cacheSet(
-                    'PMA_MYSQL_MAJOR_VERSION',
-                    PMA_MYSQL_MAJOR_VERSION
-                );
-                Util::cacheSet(
-                    'PMA_MYSQL_STR_VERSION',
-                    PMA_MYSQL_STR_VERSION
-                );
-                Util::cacheSet(
-                    'PMA_MYSQL_VERSION_COMMENT',
-                    PMA_MYSQL_VERSION_COMMENT
-                );
-                /* Detect MariaDB */
-                if (mb_strpos(PMA_MYSQL_STR_VERSION, 'MariaDB') !== false) {
-                    define('PMA_MARIADB', true);
-                } else {
-                    define('PMA_MARIADB', false);
-                }
-                Util::cacheSet(
-                    'PMA_MARIADB',
-                    PMA_MARIADB
-                );
+                define('PMA_MYSQL_INT_VERSION', 50501);
+                define('PMA_MYSQL_MAJOR_VERSION', 5);
+                define('PMA_MYSQL_STR_VERSION', '5.05.01');
+                define('PMA_MYSQL_VERSION_COMMENT', '');
+            }
+            /* Detect MariaDB */
+            if (mb_strpos(PMA_MYSQL_STR_VERSION, 'MariaDB') !== false) {
+                define('PMA_MARIADB', true);
+            } else {
+                define('PMA_MARIADB', false);
             }
         }
 
diff --git a/libraries/VersionInformation.php b/libraries/VersionInformation.php
index 49e5e4ce4d..ee69cfab53 100644
--- a/libraries/VersionInformation.php
+++ b/libraries/VersionInformation.php
@@ -276,6 +276,6 @@ class VersionInformation
      */
     protected function getMySQLVersion()
     {
-        return Util::cacheGet('PMA_MYSQL_STR_VERSION');
+        return PMA_MYSQL_STR_VERSION;
     }
 }