get_missing_block.php

<?php
$pdo = null;
function DBConnect() {
    global $pdo;
    $pdo = new PDO('mysql:host=mysql.steem-lightdb.com;dbname=steem;port=3306','steemit','steemit');
    $pdo->exec('set names utf8');
}

function DBClose() {
    global $pdo;
    $pdo = null;
}

function DBBlockNum() {
    global $pdo;
    $stmt = $pdo->prepare("select block_num from sbds_core_blocks order by block_num desc limit 1");
    $stmt->execute();
    $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
    $stmt->closeCursor();
    return $rows[0]['block_num'];
}

function BlockMissing($max) {
    global $pdo;
    $chunk = 100000;
    $num_chunks = (int)($max / $chunk) + 1;
    $start = 1;
    $missing = [];
    
    for($i=1; $i <= $num_chunks; $i++) {
        if ($i == 1) {
            $start = 1;
        } else {
            $start = $end;
        }
        $end = $start + $chunk;
        $stmt = $pdo->prepare("select block_num from sbds_core_blocks where block_num >= ".$start." and block_num < ".$end);
        $stmt->execute();
        $rows = $stmt->fetchAll(PDO::FETCH_COLUMN, 0);
        $stmt->closeCursor();
        $period_nums = range(start, $end-1);
        $tmp_missing = array_diff($period_nums, $rows);
        $missing = array_merge($missing, $tmp_missing);
        $period_nums = null;
        $tmp_missing = null;
    }
    $t = '';
    foreach($missing as $v) {
        $t .= $v.' ';
    }
    var_dump($t);die();
}

DBConnect();
$db_header = DBBlockNum();
$missing = BlockMissing($db_header);
DBClose();