MDL-55272 lib: Improve test course create performance

Use core functions that are faster for test file creation.
To support large requests for hashes, the core hash function
must support large hashes without recursion.  PHP has a default
recursion depth of 100 and long hashes don't support this.

Remove transactions as they create performance problems for larger
courses and doesn't introduce significant benefit for developers.

Performance changes meant the times were much faster, a reasonable
guess was taken on performance of an average machine.

admin/tool/generator/classes/course_backend.php

@@ -216,19 +216,19 @@ public function make() {
 
         $entirestart = microtime(true);
 
-        // Start transaction.
-        $transaction = $DB->start_delegated_transaction();
-
         // Get generator.
         $this->generator = phpunit_util::get_data_generator();
 
         // Make course.
         $this->course = $this->create_course();
-        $this->create_users();
+
         $this->create_assignments();
         $this->create_pages();
         $this->create_small_files();
         $this->create_big_files();
+
+        // Create users as late as possible to reduce regarding in the gradebook.
+        $this->create_users();
         $this->create_forum();
 
         // Log total time.
@@ -238,8 +238,6 @@ public function make() {
             echo html_writer::end_tag('ul');
         }
 
-        // Commit transaction and finish.
-        $transaction->allow_commit();
         return $this->course->id;
     }
 
@@ -435,7 +433,7 @@ private function create_small_files() {
 
             // Generate random binary data (different for each file so it
             // doesn't compress unrealistically).
-            $data = self::get_random_binary($this->limit_filesize(self::$paramsmallfilesize[$this->size]));
+            $data = random_bytes_emulate($this->limit_filesize(self::$paramsmallfilesize[$this->size]));
 
             $fs->create_file_from_string($filerecord, $data);
             $this->dot($i, $count);
@@ -444,33 +442,10 @@ private function create_small_files() {
         $this->end_log();
     }
 
-    /**
-     * Creates a string of random binary data. The start of the string includes
-     * the current time, in an attempt to avoid large-scale repetition.
-     *
-     * @param int $length Number of bytes
-     * @return Random data
-     */
-    private static function get_random_binary($length) {
-
-        $data = microtime(true);
-        if (strlen($data) > $length) {
-            // Use last digits of data.
-            return substr($data, -$length);
-        }
-        $length -= strlen($data);
-        for ($j = 0; $j < $length; $j++) {
-            $data .= chr(rand(1, 255));
-        }
-        return $data;
-    }
-
     /**
      * Creates a number of resource activities with one big file each.
      */
     private function create_big_files() {
-        global $CFG;
-
         // Work out how many files and how many blocks to use (up to 64KB).
         $count = self::$parambigfilecount[$this->size];
         $filesize = $this->limit_filesize(self::$parambigfilesize[$this->size]);
@@ -499,7 +474,7 @@ private function create_big_files() {
                 throw new coding_exception('Failed to open temporary file');
             }
             for ($j = 0; $j < $blocks; $j++) {
-                $data = self::get_random_binary($blocksize);
+                $data = random_bytes_emulate($blocksize);
                 fwrite($handle, $data);
                 $this->dot($i * $blocks + $j, $count * $blocks);
             }

admin/tool/generator/lang/en/tool_generator.php

@@ -43,10 +43,10 @@
 
 $string['coursesize_0'] = 'XS (~10KB; create in ~1 second)';
 $string['coursesize_1'] = 'S (~10MB; create in ~30 seconds)';
-$string['coursesize_2'] = 'M (~100MB; create in ~5 minutes)';
-$string['coursesize_3'] = 'L (~1GB; create in ~1 hour)';
-$string['coursesize_4'] = 'XL (~10GB; create in ~4 hours)';
-$string['coursesize_5'] = 'XXL (~20GB; create in ~8 hours)';
+$string['coursesize_2'] = 'M (~100MB; create in ~2 minutes)';
+$string['coursesize_3'] = 'L (~1GB; create in ~30 minutes)';
+$string['coursesize_4'] = 'XL (~10GB; create in ~2 hours)';
+$string['coursesize_5'] = 'XXL (~20GB; create in ~4 hours)';
 $string['coursewithoutusers'] = 'The selected course has no users';
 $string['createcourse'] = 'Create course';
 $string['createtestplan'] = 'Create test plan';

lib/classes/event/role_assigned.php

@@ -105,7 +105,8 @@ protected function get_legacy_eventdata() {
      */
     protected function get_legacy_logdata() {
         $roles = get_all_roles();
-        $rolenames = role_fix_names($roles, $this->get_context(), ROLENAME_ORIGINAL, true);
+        $neededrole = array($this->objectid => $roles[$this->objectid]);
+        $rolenames = role_fix_names($neededrole, $this->get_context(), ROLENAME_ORIGINAL, true);
         return array($this->courseid, 'role', 'assign', 'admin/roles/assign.php?contextid='.$this->contextid.'&roleid='.$this->objectid,
                 $rolenames[$this->objectid], '', $this->userid);
     }

lib/moodlelib.php

@@ -7803,20 +7803,21 @@ function random_bytes_emulate($length) {
         }
     }
     if (function_exists('openssl_random_pseudo_bytes')) {
-        // For PHP 5.3 and later with openssl extension.
+        // If you have the openssl extension enabled.
         $hash = openssl_random_pseudo_bytes($length);
         if ($hash !== false) {
             return $hash;
         }
     }
 
-    // Bad luck, there is no reliable random generator, let's just hash some unique stuff that is hard to guess.
-    $hash = sha1(serialize($CFG) . serialize($_SERVER) . microtime(true) . uniqid('', true), true);
-    // NOTE: the last param in sha1() is true, this means we are getting 20 bytes, not 40 chars as usual.
-    if ($length <= 20) {
-        return substr($hash, 0, $length);
-    }
-    return $hash . random_bytes_emulate($length - 20);
+    // Bad luck, there is no reliable random generator, let's just slowly hash some unique stuff that is hard to guess.
+    $staticdata = serialize($CFG) . serialize($_SERVER);
+    $hash = '';
+    do {
+        $hash .= sha1($staticdata . microtime(true) . uniqid('', true), true);
+    } while (strlen($hash) < $length);
+
+    return substr($hash, 0, $length);
 }
 
 /**

lib/tests/moodlelib_test.php

@@ -3047,6 +3047,9 @@ public function test_random_bytes_emulate() {
         $result = random_bytes_emulate(666);
         $this->assertSame(666, strlen($result));
 
+        $result = random_bytes_emulate(40);
+        $this->assertSame(40, strlen($result));
+
         $this->assertDebuggingNotCalled();
 
         $result = random_bytes_emulate(0);