$this->db->insert_id() giving fatal error postgresql codeigniter - codeigniter

Question

I am using Codeigniter 2.0.1 and Postgresql 8.1. My code uses transactions within try-catch blocks.
On a simple insert at times I get a "Fatal Error"
Fatal Error: Call to a member function row() on a non-object in
<...path...>/system/database/drivers/postgre/postgre_driver.php on
line 357
My Database Config is:
$db['default']['hostname'] = "localhost";
$db['default']['username'] = "***";
$db['default']['password'] = "***";
$db['default']['database'] = "***";
$db['default']['dbdriver'] = 'postgre';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = FALSE;
$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;
$db['default']['stricton'] = FALSE;
The lne of my Model code that is causing the error is "$id = $this->db->insert_id();".
I say so because the line that causes the error is within insert_id() method and it is being used only once in the model.
A code snapshot of the model is given below.
try {
// CODE TO FILL UP $data ARRAY
$this->DBquery("BEGIN");
$this->DBinsert('<TABLE NAME>', $data);
$id = $this->db->insert_id();
// SOME MORE CODE
}
catch(Exception $e) {
$this->DBquery("ROLLBACK");
//echo $e->getMessage();
return 0;
}
$this->DBquery("COMMIT");
return $id;
$this->DBquery and $this->DBinsert are custom methods made by me on a base model class which extends the CI_Model class. These methods function full well.
Below is the insert_id method in postgre_driver.php and line 357 is "$row = $query->row();"
function insert_id()
{
$v = $this->_version();
$v = $v['server'];
$table = func_num_args() > 0 ? func_get_arg(0) : NULL;
$column = func_num_args() > 1 ? func_get_arg(1) : NULL;
if ($table == NULL && $v >= '8.1')
{
$sql='SELECT LASTVAL() as ins_id';
}
elseif ($table != NULL && $column != NULL && $v >= '8.0')
{
$sql = sprintf("SELECT pg_get_serial_sequence('%s','%s') as seq", $table, $column);
$query = $this->query($sql);
$row = $query->row();
$sql = sprintf("SELECT CURRVAL('%s') as ins_id", $row->seq);
}
elseif ($table != NULL)
{
// seq_name passed in table parameter
$sql = sprintf("SELECT CURRVAL('%s') as ins_id", $table);
}
else
{
return pg_last_oid($this->result_id);
}
$query = $this->query($sql);
$row = $query->row(); // LINE 357
return $row->ins_id;
}
Its so more confusing because the problem is not always. It happens sometimes but with a good enough frequency to hamper work. The system is being used by about 8-10 users and so I guess concurrency should not be an issue.
Also, I am using pconnect and number of connections is unlimited.

Answer 1

This sounds like maybe some of your insert statements are failing. If something errors out inside of a transaction like this, it can invalidate the transaction. If you look in the log file, you may find entries like "current transaction is aborted, commands ignored until end of transaction." (What's happening is the $query variable in the insert_id function doesn't receive a valid query result value, so calling functions on it fails at that point)
The best way to handle this is probably to modify your custom DBinsert function to return a value indicating the success or failure of the insert operation. (You should just be able to return the value of whatever insert command you're running internally)
Then, you can do something like this:
$insert_ret_val = $this->DBinsert('<TABLE NAME>', $data);
if($insert_ret_val){
//insert success!
$id = $this->db->insert_id();
}else{
//handle failed insert here, rollback, whatever
}