Re: BUG #5244: Attempting to rollback to a savepoint after receiving an error with state 55000 the process hangs

Robert Haas wrote:
> On Mon, Dec 14, 2009 at 11:15 PM, Philip Graham <philip(at)lightbox(dot)org> wrote:
>
>> The following bug has been logged online:
>>
>> Bug reference: 5244
>> Logged by: Philip Graham
>> Email address: philip(at)lightbox(dot)org
>> PostgreSQL version: 8.3.8
>> Operating system: Linux
>> Description: Attempting to rollback to a savepoint after receiving an
>> error with state 55000 the process hangs
>> Details:
>>
>> This may be a PHP so please excure me if it is.
>>
>> <?php
>> $pdo = new PDO('pgsql:host=localhost;dbname=a_db', 'a_user', 'my_pass');
>> $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
>>
>> echo 'Creating test objects'."\n";
>> $pdo->query('CREATE SEQUENCE test_seq');
>>
>> echo 'Setup complete'."\n";
>> $pdo->beginTransaction();
>>
>> try {
>> echo 'Setting savepoint'."\n";
>> $pdo->query('SAVEPOINT pre_id_fetch');
>> echo 'Fetching value'."\n";
>> $stmt = $pdo->query('SELECT currval(\'test_seq\');');
>> $curId = $stmt->fetchColumn();
>> echo 'Releasing savepoint'."\n";
>> $pdo->query('RELEASE SAVEPOINT pre_id_fetch');
>> } catch (PDOException $e) {
>> echo 'Rolling back'."\n";
>> $pdo->query('ROLLBACK TO pre_id_fetch');
>> $curId = 0;
>> }
>>
>> echo 'Cur Id: ',$curId,"\n";
>>
>>
>> Running this code it hangs after echoing 'Rolling back', but only hangs
>> every other execution (assuming the sequence was deleted first).
>>
>
> I can't reproduce this using psql. Could you try? I am guessing that
> PHP is doing something funky, but I'm not really sure what. I do
> notice that you don't seem to have an endTransaction() or similar to
> match the beginTransaction() - could that be relevant?
>
> ...Robert
>
I also can't reproduce using psql, I'm suspecting it's a PHP thing. If
I use phpPgAdmin to watch what the connection is doing, when the script
hangs it loops through:

1. ROLLBACK TO pre_fetch_id;
2. DEALLOCATE pdo_stmt_<someGeneratedId>;
3. <idle in transaction>

<someGeneratedId> is always the same.

I'm going to post the bug with PHP and see if I can get help there.

Thanks,
Philip