[PHP-DEV] Bug #13287 Updated: MySQL, PHP and a random problem From: derick <email protected>
Date: 09/14/01

ID: 13287
Updated by: derick
Reported By: alberty <email protected>
Old Status: Open
Status: Closed
Bug Type: MySQL related
Operating System: i686-pc-linux-gnu
PHP Version: 4.0CVS-2001-09-13
New Comment:

Not a bug in PHP, but in MySQl. Closing

Previous Comments:
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[2001-09-14 04:36:35] alberty <email protected>

Yes, with
mysql -e "select ID from footest order by rand() limit 8;"

the same problem.

okay, i post it to the mysql dev. forum.

Regards, 

-- 
Steve

------------------------------------------------------------------------

[2001-09-13 13:48:29] hholzgra <email protected>

i guess it's timing-related (and definetly on the MySQL side)

what happens if you call

mysql ... -e "select ID from footest order by rand() limit 8;"

from command line several times instead of typing the query into the same client multiple times?

my first guess would be that you get similar not-so-random results as the RAND() result seems to be related to MySQL client runtime somehow ...

------------------------------------------------------------------------

[2001-09-13 12:31:08] alberty <email protected>

Hi,

i have found a mystic behavior with
MySQL and PHP.

The follow code describes a problem which i have
only observe in the combination between PHP and MySQL.

i have test it with PHP (406,407dev,408dev) and
MySQL (3.23.39-3.23.42) under suse-linux.

okay, lets go to the problem.

First make a simple table like:

// SQL-Dump
CREATE TABLE footest (
  ID int(10) unsigned NOT NULL default '0',
  KEY ID (ID)
) TYPE=MyISAM;

then push many rows in the table with increasing numbers!

<?php
for ($i=1;$i<=60000;$i++){
	mysql_query("insert into footest (ID) values($i)");
}
?>

okay, and now the miracle comes with this script:

<?php
$result=mysql_query("select ID from footest order by rand() limit 8");
if ($result!=false) while ($tmp=mysql_fetch_assoc($result)){
	echo $tmp['ID']."<br>";
}
else echo mysql_error();
?>

i have attached 5 series from the little code:

Call 1: 52839,36271, 2555,42892,32471,13967,52990,27917
Call 2: 52823,36255, 2539,42876,32455,13951,52974,27901
Call 3: 52775,36207, 2491,42828,32407,13903,52926,27853
Call 4: 52751,36183, 2467,42804,32383,13879,52902,27829
Call 5: 52735,36167, 2451,42788,32367,13863,52886,27813

you see the problem ? No, okay make the same test under
the mysql console. 

Type:
"select ID from footest order by rand() limit 8;"

and mysql results really random rows. strange problem ;-)

i hope some developer have an idea, where the problem is, but
perhaps it is a mysql problem.

Regards,

-- 
Steve

------------------------------------------------------------------------

Edit this bug report at http://bugs.php.net/?id=13287&edit=1

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