From 9043466103365009afd0cc52c85576f0a88cda1f Mon Sep 17 00:00:00 2001
From: "Eloy Lafuente (stronk7)" <stronk7@moodle.org>
Date: Sun, 28 Apr 2013 18:12:38 +0200
Subject: [PATCH] MDL-39389 add databasemeta cache to ms/oci drivers

---
 lib/dml/mssql_native_moodle_database.php  | 19 ++++++++++++++-----
 lib/dml/oci_native_moodle_database.php    | 19 ++++++++++++++-----
 lib/dml/sqlsrv_native_moodle_database.php | 18 +++++++++++++-----
 3 files changed, 41 insertions(+), 15 deletions(-)

diff --git a/lib/dml/mssql_native_moodle_database.php b/lib/dml/mssql_native_moodle_database.php
index 3191d5f0fd5..e1ea067c5e9 100644
--- a/lib/dml/mssql_native_moodle_database.php
+++ b/lib/dml/mssql_native_moodle_database.php
@@ -410,11 +410,16 @@ class mssql_native_moodle_database extends moodle_database {
      * @return array array of database_column_info objects indexed with column names
      */
     public function get_columns($table, $usecache=true) {
-        if ($usecache and isset($this->columns[$table])) {
-            return $this->columns[$table];
+
+        if ($usecache) {
+            $properties = array('dbfamily' => $this->get_dbfamily(), 'settings' => $this->get_settings_hash());
+            $cache = cache::make('core', 'databasemeta', $properties);
+            if ($data = $cache->get($table)) {
+                return $data;
+            }
         }
 
-        $this->columns[$table] = array();
+        $structure = array();
 
         if (!$this->temptables->is_temptable($table)) { // normal table, get metadata from own schema
             $sql = "SELECT column_name AS name,
@@ -494,11 +499,15 @@ class mssql_native_moodle_database extends moodle_database {
             // Process binary
             $info->binary = $info->meta_type == 'B' ? true : false;
 
-            $this->columns[$table][$info->name] = new database_column_info($info);
+            $structure[$info->name] = new database_column_info($info);
         }
         $this->free_result($result);
 
-        return $this->columns[$table];
+        if ($usecache) {
+            $result = $cache->set($table, $structure);
+        }
+
+        return $structure;
     }
 
     /**
diff --git a/lib/dml/oci_native_moodle_database.php b/lib/dml/oci_native_moodle_database.php
index f5cce9dbba0..e13be7fd9cd 100644
--- a/lib/dml/oci_native_moodle_database.php
+++ b/lib/dml/oci_native_moodle_database.php
@@ -469,15 +469,20 @@ class oci_native_moodle_database extends moodle_database {
      * @return array array of database_column_info objects indexed with column names
      */
     public function get_columns($table, $usecache=true) {
-        if ($usecache and isset($this->columns[$table])) {
-            return $this->columns[$table];
+
+        if ($usecache) {
+            $properties = array('dbfamily' => $this->get_dbfamily(), 'settings' => $this->get_settings_hash());
+            $cache = cache::make('core', 'databasemeta', $properties);
+            if ($data = $cache->get($table)) {
+                return $data;
+            }
         }
 
         if (!$table) { // table not specified, return empty array directly
             return array();
         }
 
-        $this->columns[$table] = array();
+        $structure = array();
 
         // We give precedence to CHAR_LENGTH for VARCHAR2 columns over WIDTH because the former is always
         // BYTE based and, for cross-db operations, we want CHAR based results. See MDL-29415
@@ -656,10 +661,14 @@ class oci_native_moodle_database extends moodle_database {
                 $info->meta_type     = '?';
             }
 
-            $this->columns[$table][$info->name] = new database_column_info($info);
+            $structure[$info->name] = new database_column_info($info);
         }
 
-        return $this->columns[$table];
+        if ($usecache) {
+            $result = $cache->set($table, $structure);
+        }
+
+        return $structure;
     }
 
     /**
diff --git a/lib/dml/sqlsrv_native_moodle_database.php b/lib/dml/sqlsrv_native_moodle_database.php
index 09fa92efc37..f5992b46f26 100644
--- a/lib/dml/sqlsrv_native_moodle_database.php
+++ b/lib/dml/sqlsrv_native_moodle_database.php
@@ -476,11 +476,15 @@ class sqlsrv_native_moodle_database extends moodle_database {
      * @return array array of database_column_info objects indexed with column names
      */
     public function get_columns($table, $usecache = true) {
-        if ($usecache and isset($this->columns[$table])) {
-            return $this->columns[$table];
+        if ($usecache) {
+            $properties = array('dbfamily' => $this->get_dbfamily(), 'settings' => $this->get_settings_hash());
+            $cache = cache::make('core', 'databasemeta', $properties);
+            if ($data = $cache->get($table)) {
+                return $data;
+            }
         }
 
-        $this->columns[$table] = array ();
+        $structure = array();
 
         if (!$this->temptables->is_temptable($table)) { // normal table, get metadata from own schema
             $sql = "SELECT column_name AS name,
@@ -560,11 +564,15 @@ class sqlsrv_native_moodle_database extends moodle_database {
             // Process binary
             $info->binary = $info->meta_type == 'B' ? true : false;
 
-            $this->columns[$table][$info->name] = new database_column_info($info);
+            $structure[$info->name] = new database_column_info($info);
         }
         $this->free_result($result);
 
-        return $this->columns[$table];
+        if ($usecache) {
+            $result = $cache->set($table, $structure);
+        }
+
+        return $structure;
     }
 
     /**