note 93622 deleted from function.mysql-insert-id by cmb
| From: | cmb@php.net | Date: | Sun, 16 Feb 2020 13:32:41 +0000 |
| Subject: | note 93622 deleted from function.mysql-insert-id by cmb | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-214121@lists.php.net to get a copy of this message | ||
Note Submitter: RPaseur at NationalPres dot org
----
Apparently the value returned by mysql_insert_id() may be correct for BIGINT auto_increment keys
below the value of INT, but it may wrap to negative when the BIGINT auto_increment passes the
largest signed value of INT. A timebomb for very large tables...
PHP 5.2.10, MySQL 5.0.81, assume the connection and selection...
<?php
// CREATE A TABLE AND ALTER IT TO A HIGH INDEX NUMBER
$sql = "CREATE TEMPORARY TABLE noise ( id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY )
ENGINE=MEMORY";
if (!$res = mysql_query($sql)) die(mysql_error());
$sql = "ALTER TABLE noise AUTO_INCREMENT = 2147483646";
if (!$res = mysql_query($sql)) die(mysql_error());
// INSERT DATA TO ADD TO THE AUTO_INCREMENT INDEX
$kount = 0;
while ($kount < 3)
{
$sql = "INSERT INTO noise () VALUES ()";
if (!$res = mysql_query($sql)) die(mysql_error());
$nid = mysql_insert_id($dbcx);
var_dump($nid);
$kount++;
}
// PRODUCES THIS
// int(2147483646)
// int(2147483647)
// int(-2147483648)
?>