Question

Cross posted form the codeigniter forum, where I got crickets.

I’ve got a query which I use two left joins and several inner joins, it consistently returns a connection reset error in firefox and no error message in the apache logs.

If I remove the ‘left’ arguments the same error does not occur, if I run the SQL from $this->db->last_query() directly in the DB adding the LEFT joins back in, it comes back properly (either in phpMyAdmin or commandline).

The “inner” arguments don’t need to be passed, I put them in there to experiment.

$this->db->select('votes.uid AS voterUID, comments.uid AS voteeUID, voteTypes.id AS voteTypeID, userratingVoter.level AS voterLevel, userratingVotee.level AS voteeLevel');

$this->db->from('votes');

# Join the comments table on comments.id = votes.cid
$this->db->join('comments', 'comments.id = votes.cid', 'inner');

# Join the userauth table for admin WHERE clause below
$this->db->join('userauth',  'userauth.uid = votes.uid', 'inner');

# Join the votesTypes table for the WHERE IN clause below
$this->db->join('voteTypes', 'voteTypes.id = votes.voteid', 'inner');

# Join the userrating table twice once for the Voter once for the Votee
$this->db->join('userrating AS userratingVotee', 'userratingVotee.uid = comments.uid', 'left');
$this->db->join('userrating AS userratingVoter', 'userratingVoter.uid = votes.uid', 'left');

# Where in valid Vote Types
# Valid Vote Types: helpful, interesting, correct, incorrect
#                   5        4            2        7
$validVoteTypes = array(5,4,2,7);
$this->db->where_in('votes.voteid', $validVoteTypes);

# Where vote is active.
$this->db->where('votes.active',1);

# Where timestamp is greater than the last run timestamp.
$this->db->where('votes.timestamp >',$lastrun);

# Only standard user votes count, may have to update this if we get other authids
$this->db->where('userauth.authid',2);

Broken up SQL from $this->db->last_query()… works in phpMyAdmin and from commandline.

SELECT `votes`.`uid` AS voterUID, `comments`.`uid` AS voteeUID, `voteTypes`.`id` AS voteTypeID, `userratingVoter`.`level` AS voterLevel, `userratingVotee`.`level` AS voteeLevel

FROM (`votes`)

INNER JOIN `comments` ON `comments`.`id` = `votes`.`cid`
INNER JOIN `userauth` ON `userauth`.`uid` = `votes`.`uid`
INNER JOIN `voteTypes` ON `voteTypes`.`id` = `votes`.`voteid`

LEFT JOIN `userrating` AS userratingVotee ON `userratingVotee`.`uid` = `comments`.`uid`
LEFT JOIN `userrating` AS userratingVoter ON `userratingVoter`.`uid` = `votes`.`uid`

WHERE `votes`.`voteid` IN (5, 4, 2, 7)
 AND `votes`.`active` = 1
 AND `votes`.`timestamp` > '2012-03-01 00:00:00'
 AND `userauth`.`authid` = 2

Further if I use a standard query instead of the active record syntax, it produces the same results.

$sql = "SELECT `votes`.`uid` AS voterUID, `comments`.`uid` AS voteeUID, `voteTypes`.`id` AS voteTypeID, `userratingVoter`.`level` AS voterLevel, `userratingVotee`.`level` AS voteeLevel FROM (`votes`) INNER JOIN `comments` ON `comments`.`id` = `votes`.`cid` INNER JOIN `userauth` ON `userauth`.`uid` = `votes`.`uid` INNER JOIN `voteTypes` ON `voteTypes`.`id` = `votes`.`voteid` LEFT JOIN `userrating` AS userratingVotee ON `userratingVotee`.`uid` = `comments`.`uid` LEFT JOIN `userrating` AS userratingVoter ON `userratingVoter`.`uid` = `votes`.`uid` WHERE `votes`.`voteid` IN (5, 4, 2, 7) AND `votes`.`active` = 1 AND `votes`.`timestamp` > '2012-03-01 00:00:00' AND `userauth`.`authid` = 2";

$query = $this->db->query($sql);

If I use a standard JOIN instead of LEFT JOIN for either the error does not occur, though it doesn’t return the data I need.

Server Info:

Apache/2.2.14 (Ubuntu)
PHP/5.3.2
MySQL 5.1.63
CodeIgniter 2.1.2

application/config/database.php

$active_group = 'default';
$active_record = TRUE;

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'some_user';
$db['default']['password'] = 'some_pass';
$db['default']['database'] = 'some_db';
$db['default']['dbdriver'] = 'mysqli';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;  

Answer 1

The reason you are seeing the error in Firefox is presumably because PHP is exiting abnormally for some reason. If you can find the error log on your web server you may be able to see why. EDIT: Just spotted that you’d looked in the error logs already; maybe PHP isn’t set up to log there?

The most likely cause is that the query is returning so much data that PHP is running out of either memory or processing time trying to process it all. If that is the case, you might want to try using LIMIT and OFFSET clauses in the query to get a “page” of data at a time.