KO3, PostgreSQL, Transactions, and PDOException - exception

Question

I've run into an issue that I'm hoping to get a little help on. I'm using the following:
Kohana 3.0.7
PostgreSQL 8.4
Transactions in PostgreSQL using
$db->query(NULL, 'BEGIN', FALSE)
$db->query(NULL, 'ROLLBACK', FALSE);
$db->query(NULL, 'COMMIT', FALSE);
The issue is that when I send a query to the database that results in a postgres error within a transaction my system freezes up. When I send the same query to the database without wrapping it in a transaction the PDO error is reported back just as expected. Here is an exmaple:
This first example works fine and duplicate key value violates unique constraint "pk_test_table" error is returned:
$query = DB::query(Database::INSERT, 'INSERT INTO test_table (test_table_id, test_table_val) VALUES (:id, :value)';
$query->param(':id', 1);
$query->param(':value', "test value");
try
{
$result = $query->execute($db);
}
catch (Exception $e)
{
echo 'Caught exception: ', $e->getMessage(), "\n";
}
This second example causes my system to freeze (I can't tell if it's an infinite loop, or some other freeze):
$db->query(NULL, 'BEGIN', FALSE);
$query = DB::query(Database::INSERT, 'INSERT INTO test_table (test_table_id, test_table_val) VALUES (:id, :value)';
$query->param(':id', 1);
$query->param(':value', "test value");
try
{
$result = $query->execute($db);
}
catch (Exception $e)
{
echo 'Caught exception: ', $e->getMessage(), "\n";
}
$db->query(NULL, 'ROLLBACK', FALSE);
As you can see the only difference is that the second example is wrapped in a transaction.
Any ideas on what is going on? Any suggestions for things to try?

Answer 1

I found a way to work around the issue. Not sure if this is a bug in PDO or some other part of the tool set but what I'm doing to work around is the following:
$exception_exists = FALSE;
$db->query(NULL, 'BEGIN', FALSE);
$query = DB::query(Database::INSERT, 'INSERT INTO test_table (test_table_id, test_table_val) VALUES (:id, :value)';
$query->param(':id', 1);
$query->param(':value', "test value");
try
{
$result = $query->execute($db);
}
catch (Exception $e)
{
echo 'Caught exception: ', $e->getMessage(), "\n";
$exception_exists = TRUE;
}
if (!$exception_exists)
{
$db->query(NULL, 'ROLLBACK', FALSE);
}
By adding the variable $exception_exists in the catch I can then act of that if there is no exception. If there is an exception and I try to ROLLBACK or COMMIT then I get the freezing behavior.
This works for now but I wouldn't call it elegant.