optimize ocelot drain check query

app/DB.php

@@ -186,8 +186,9 @@ class DB extends Base {
             SELECT count(*)
             FROM performance_schema.processlist
             WHERE COMMAND NOT IN ('Sleep')
-                AND TIME > 1200;
-        ");
+                AND TIME > ?
+            ", MYSQL_SLOW_QUERY_TIMEOUT
+        );
     }
 
     public static function lookupDirection(string $direction): Direction {

app/DB/MysqlTable.php

@@ -87,6 +87,17 @@ class MysqlTable extends AbstractTable {
         );
     }
 
+    public function recentUpdate(int $seconds): bool {
+        return (bool)self::$db->scalar("
+            SELECT 1
+            FROM information_schema.tables
+            WHERE table_schema = ?
+                AND table_name = ?
+                AND update_time > now() - INTERVAL ? SECOND
+            ", MYSQL_DB, $this->name, $seconds
+        );
+    }
+
     public function stats(): array {
         return self::$db->rowAssoc("
             SELECT t.TABLE_ROWS,

app/Tracker.php

@@ -341,4 +341,14 @@ class Tracker extends Base {
         ");
         return self::$db->to_array(false, MYSQLI_ASSOC);
     }
+
+    public function recentUpdate(int $seconds): bool {
+        return (bool)self::$db->scalar("
+            SELECT 1
+            FROM xbt_files_users
+            WHERE mtime > unix_timestamp(now() - INTERVAL ? SECOND)
+            LIMIT 1
+            ", $seconds
+        );
+    }
 }

app/User/Activity.php

@@ -75,22 +75,6 @@ class Activity extends \Gazelle\BaseUser {
         return $this;
     }
 
-    public function setDb(\Gazelle\DB $dbMan): static {
-        if ($this->user->permitted('admin_site_debug')) {
-            $longRunning = $dbMan->longRunning();
-            if ($longRunning > 0) {
-                $message = "$longRunning long-running DB operation" . plural($longRunning);
-                $this->setAlert("<span title=\"$message\" class=\"sys-error\">DB</span>");
-            }
-            // If Ocelot can no longer write to xbt_files_users, it will drain after an hour
-            // Look for database locks and check the Ocelot log
-            if (!self::$db->scalar('SELECT fid FROM xbt_files_users LIMIT 1')) {
-                $this->setAlert('<span style="color: red">Ocelot not updating!</span>');
-            }
-        }
-        return $this;
-    }
-
     public function setPayment(\Gazelle\Manager\Payment $payMan): static {
         if ($this->user->permitted('admin_manage_payments')) {
             $soon = $payMan->soon();

app/View.php

@@ -48,7 +48,6 @@ class View extends Base {
                 ->setReport(new Stats\Report())
                 ->setPayment($payMan)
                 ->setApplicant(new Manager\Applicant())
-                ->setDb(new DB())
                 ->setScheduler(new TaskScheduler())
                 ->setSSLHost(new Manager\SSLHost())
                 ->setAutoReport(
@@ -58,6 +57,23 @@ class View extends Base {
                     )
                 );
 
+            if ($user->permitted('admin_site_debug')) {
+                $longRunning = new DB()->longRunning();
+                if ($longRunning > 0) {
+                    $message = "$longRunning long-running DB operation" . plural($longRunning);
+                    $activity->setAlert("<span title=\"$message\" class=\"sys-error\">DB</span>");
+                }
+                // Check that Ocelot is still writing to xbt_files_users.
+                // If not, look for database locks and check the Ocelot log
+
+                if (!new Tracker()->recentUpdate(TRACKER_REFRESH_TIMEOUT)) {
+                    $activity->setAlert('<span title="No update received from tracker within '
+                        . Util\Time::convertSeconds(TRACKER_REFRESH_TIMEOUT)
+                        . '" class="sys-error">TRACKER</span>'
+                    );
+                }
+            }
+
             $threshold = new Manager\SiteOption()
                 ->findValueByName('download-warning-threshold');
             if ($threshold) {

lib/config.php

@@ -194,6 +194,9 @@ defined('MYSQL_RO_USER') or define('MYSQL_RO_USER', 'gazro');
 // The password of the above account.
 defined('MYSQL_RO_PASS') or define('MYSQL_RO_PASS', 'passro');
 
+// Warn if there is a query that has been running for too long
+defined('MYSQL_SLOW_QUERY_TIMEOUT') or define('MYSQL_SLOW_QUERY_TIMEOUT', 1200);
+
 // The username of the Phinx account (used for schema modifications).
 // In production, this account will have a different set of grants compared
 // to the website account (so that if the website account is compromised, it
@@ -292,6 +295,12 @@ defined('TRACKER_NAME') or define('TRACKER_NAME', '127.0.0.1' . ":" . TRACKER_PO
 // be exactly 32 alphanumeric characters.
 defined('TRACKER_SECRET') or define('TRACKER_SECRET', '00000000000000000000000000000000');
 
+// How long to wait in the absense of an update from the tracker to warn of a
+// problem? Busy with millions of peears receive multiple updates per second.
+// Sites with a few thousand peers or less may not see an update for several
+// seconds.
+defined('TRACKER_REFRESH_TIMEOUT') or define('TRACKER_REFRESH_TIMEOUT', 5);
+
 // Second shared secret that is compiled into Ocelot (see config.cpp). Must
 // be exactly 32 alphanumeric characters.
 defined('TRACKER_REPORTKEY') or define('TRACKER_REPORTKEY', '00000000000000000000000000000000');

tests/phpunit/DbTest.php

@@ -363,6 +363,8 @@ class DbTest extends TestCase {
             ),
             'mysql-fkey-list'
         );
+        // not a problem that the table does not exist, the SQL is being tested
+        $this->assertFalse($bad->recentUpdate(600), 'mysql-table-recent-update');
     }
 
     public function testPgTable(): void {

tests/phpunit/TrackerTest.php

@@ -182,4 +182,21 @@ class TrackerTest extends TestCase {
         $this->assertEquals(1, $tracker->expireFreeleechTokens("$userId:$torrentId,$userId:$fakeId"), 'tracker-expire-tokens');
         $downloader->remove();
     }
+
+    public function testTrackerUpdate(): void {
+        $this->user = Helper::makeUser('trkfree.' . randomString(10), 'tracker');
+        $this->user->requestContext()->setViewer($this->user);
+        $this->torrent = Helper::makeTorrentMusic(
+            Helper::makeTGroupMusic(
+                name:       'tracker ' . randomString(10),
+                artistName: [[ARTIST_MAIN], ['Tracker Girl ' . randomString(12)]],
+                tagName:    ['trap'],
+                user:       $this->user,
+            ),
+            user:  $this->user,
+            title: 'tracker ' . randomString(10),
+        );
+        Helper::generateTorrentSeed($this->torrent, $this->user);
+        $this->assertTrue(new Tracker()->recentUpdate(60), 'tracker-recent-update');
+    }
 }

tests/phpunit/UserActivityTest.php

@@ -30,7 +30,6 @@ class UserActivityTest extends TestCase {
 
         $this->assertInstanceOf(User\Activity::class, $activity->configure(), 'user-activity-configure');
         $this->assertInstanceOf(User\Activity::class, $activity->setApplicant(new Manager\Applicant()), 'user-activity-applicant');
-        $this->assertInstanceOf(User\Activity::class, $activity->setDb(new DB()), 'user-activity-db');
         $this->assertInstanceOf(User\Activity::class, $activity->setPayment(new Manager\Payment()), 'user-activity-payment');
         $this->assertInstanceOf(User\Activity::class, $activity->setReferral(new Manager\Referral()), 'user-activity-referral');
         $this->assertInstanceOf(User\Activity::class, $activity->setReport(new Stats\Report()), 'user-activity-report');