From d3a6b91aecfdc371cbb081e6235f1632d9b46430 Mon Sep 17 00:00:00 2001
From: Jonathan Champ <jonathan_champ@ncsu.edu>
Date: Fri, 16 Dec 2016 12:20:45 -0500
Subject: [PATCH] MDL-57427 cache: Use perfdebug only when enabled

---
 cache/classes/loaders.php  |  2 +-
 cache/tests/cache_test.php | 53 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/cache/classes/loaders.php b/cache/classes/loaders.php
index 7a0adc6e6f2..3c5bd423ccb 100644
--- a/cache/classes/loaders.php
+++ b/cache/classes/loaders.php
@@ -213,7 +213,7 @@ class cache implements cache_loader {
         $this->definition = $definition;
         $this->store = $store;
         $this->storetype = get_class($store);
-        $this->perfdebug = !empty($CFG->perfdebug);
+        $this->perfdebug = (!empty($CFG->perfdebug) and $CFG->perfdebug > 7);
         if ($loader instanceof cache_loader) {
             $this->loader = $loader;
             // Mark the loader as a sub (chained) loader.
diff --git a/cache/tests/cache_test.php b/cache/tests/cache_test.php
index 965a61b4b80..ac6bfed2c08 100644
--- a/cache/tests/cache_test.php
+++ b/cache/tests/cache_test.php
@@ -2172,4 +2172,57 @@ class core_cache_testcase extends advanced_testcase {
         $this->assertEquals(0, $endstats[$requestid]['stores']['cachestore_static']['sets'] -
             $startstats[$requestid]['stores']['cachestore_static']['sets']);
     }
+
+    public function test_performance_debug_off() {
+        global $CFG;
+        $this->resetAfterTest(true);
+        $CFG->perfdebug = 7;
+
+        $instance = cache_config_testing::instance();
+        $applicationid = 'phpunit/applicationperfoff';
+        $instance->phpunit_add_definition($applicationid, array(
+            'mode' => cache_store::MODE_APPLICATION,
+            'component' => 'phpunit',
+            'area' => 'applicationperfoff'
+        ));
+        $sessionid = 'phpunit/sessionperfoff';
+        $instance->phpunit_add_definition($sessionid, array(
+            'mode' => cache_store::MODE_SESSION,
+            'component' => 'phpunit',
+            'area' => 'sessionperfoff'
+        ));
+        $requestid = 'phpunit/requestperfoff';
+        $instance->phpunit_add_definition($requestid, array(
+            'mode' => cache_store::MODE_REQUEST,
+            'component' => 'phpunit',
+            'area' => 'requestperfoff'
+        ));
+
+        $application = cache::make('phpunit', 'applicationperfoff');
+        $session = cache::make('phpunit', 'sessionperfoff');
+        $request = cache::make('phpunit', 'requestperfoff');
+
+        // Check that no stats are recorded for these definitions yet.
+        $stats = cache_helper::get_stats();
+        $this->assertArrayNotHasKey($applicationid, $stats);
+        $this->assertArrayNotHasKey($sessionid, $stats);
+        $this->assertArrayNotHasKey($requestid, $stats);
+
+        // Trigger cache misses, cache sets and cache hits.
+        $this->assertFalse($application->get('missMe'));
+        $this->assertTrue($application->set('setMe', 1));
+        $this->assertEquals(1, $application->get('setMe'));
+        $this->assertFalse($session->get('missMe'));
+        $this->assertTrue($session->set('setMe', 3));
+        $this->assertEquals(3, $session->get('setMe'));
+        $this->assertFalse($request->get('missMe'));
+        $this->assertTrue($request->set('setMe', 4));
+        $this->assertEquals(4, $request->get('setMe'));
+
+        // Check that no stats are being recorded for these definitions.
+        $endstats = cache_helper::get_stats();
+        $this->assertArrayNotHasKey($applicationid, $endstats);
+        $this->assertArrayNotHasKey($sessionid, $endstats);
+        $this->assertArrayNotHasKey($requestid, $endstats);
+    }
 }