db profiler

bootstrap.php

<?php
// add to bootstrap.php
register_shutdown_function(function (){
    if (strpos(@$_SERVER['HTTP_ACCEPT'], 'text/html') !== false) {
        /** @var \Magento\Framework\App\Resource $adapter */
        $adapter =  \Magento\Framework\App\ObjectManager::getInstance()
            ->get('Magento\Framework\App\ResourceConnection');
        // composer.phar  require "jdorn/sql-formatter:1.3.*@dev"
        // require_once '/home/user/.composer/vendor/jdorn/sql-formatter/lib/SqlFormatter.php';
        /** @var Zend_Db_Profiler $profiler */
        $profiler = $adapter->getConnection('read')->getProfiler();
        if ($profiler->getEnabled()) {
            echo "<table cellpadding='0' cellspacing='0' border='0'>";
            echo '<tr><th>', $profiler->getTotalElapsedSecs(), 's ','</th><th>', $profiler->getTotalNumQueries() , 'queries', '</th><th>', microtime(1) - $_SERVER['REQUEST_TIME_FLOAT'], '</th></tr>';
            foreach ($profiler->getQueryProfiles() as $query) {
                /** @var Zend_Db_Profiler_Query $query*/
                echo '<tr>';
                echo '<td>', number_format(1000 * $query->getElapsedSecs(), 2), 'ms', '</td>';
                echo '<td>', $query->getQuery(), '</td>';
                echo '</tr>';
            }
        }
    }
});

env.php

'db' => 
array (
  'table_prefix' => '',
  'connection' => 
  array (
    'default' => 
    array (
      'host' => 'localhost',
      'dbname' => 'magento2',
      'username' => 'root',
      'password' => '',
      'model' => 'mysql4',
      'initStatements' => 'SET NAMES utf8;',
      'active' => '1',
        'profiler' =>[ 'enabled' =>1] // << add this line
    ),
  ),
),