From 42d54a938add52cd2f6961421fc679162dca5353 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 600b473687..db86343fb3 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 a49a1b97b5..dcfa362991 100644
--- a/libraries/VersionInformation.php
+++ b/libraries/VersionInformation.php
@@ -269,6 +269,6 @@ class VersionInformation
      */
     protected function getMySQLVersion()
     {
-        return Util::cacheGet('PMA_MYSQL_STR_VERSION');
+        return PMA_MYSQL_STR_VERSION;
     }
 }