Bug #79872 [Opn]: Can't commit with pending unbuffert results
Edit report at https://bugs.php.net/bug.php?id=79872&edit=1
ID: 79872
Updated by: cmb@php.net
Reported by: brian at statagroup dot com
-Summary: Semantic Language inconsistency when using commit
and 2 statements.
+Summary: Can't commit with pending unbuffert results
Status: Open
Type: Bug
Package: PDO MySQL
Operating System: Linux
PHP Version: master-Git-2020-07-18 (Git)
Block user comment: N
Private report: N
New Comment:
Thank for reporting! This is not related to commit 51cdd3d[1],
tough. This commit just fixed the return value, so that
::commit() properly returns false for versions which have that
fix.
And actually, this issue is not particularly related to transactions
at all. Consider the following modified reproduce script:
<?php
// connect and create table as before, but also set PDO::ERRMODE_WARNING
$sql = 'INSERT INTO pdo_bug_test (value1, value2) VALUES (1, 2);';
$sql .= 'INSERT INTO pdo_bug_test (value1, value2) VALUES (3, 4);';
$statement = $connection->prepare($sql); $statement->execute();
print_r($connection->query('SELECT * FROM pdo_bug_test')->fetchAll());
?>
That raises the following warning:
Warning: PDO::query(): SQLSTATE[HY000]: General error: 2014 Cannot
execute queries while other unbuffered queries are active.
Consider using PDOStatement::fetchAll(). Alternatively, if your
code is only ever going to run against mysql, you may enable query
buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY
attribute. in %s on line %d
The failing ::commit() doesn't show that warning due to bug #66528.
To make the code work as desired (without the need for buffered
queries), you'd need to call $statement->nextRowset() after
executing the multi-statement (or to destroy the PDOStatement,
what would do that implicitely; that is why the code without the
variable works).
I tend to change this ticket to doc problem.
[1] <https://github.com/php/php-src/commit/51cdd3dc50af88461d83aec0fac1dca83400b58f>
Previous Comments:
------------------------------------------------------------------------
[2020-07-18 13:49:45] brian at statagroup dot com
fixing email address
------------------------------------------------------------------------
[2020-07-18 13:46:49] brian at statagroup dot com
Description:
------------
Hypothetically there is no difference between what these two examples do (except for the
introduction of a variable).
ex1.
$statement = $connection->prepare($sql);
$statement->execute();
ex2.
$connection->prepare($sql)->execute();
In practice, the first example fails under specific and reproducible conditions.
Test script:
---------------
I've created a full demonstration of the issue on github using PHP docker images.
https://github.com/Incognito/php-pdo_mysql-defect-evidence
$connection = new PDO('mysql:host=db;port=3306;dbname=mysql', 'root',
'example', []);
$connection->prepare('DROP TABLE IF EXISTS pdo_bug_test;')->execute();
$connection->prepare('CREATE TABLE pdo_bug_test (value1 VARCHAR(10), value2
INT);')->execute();
$connection->beginTransaction();
$sql = 'INSERT INTO pdo_bug_test (value1, value2) VALUES (1, 2);';
$sql .= 'INSERT INTO pdo_bug_test (value1, value2) VALUES (3, 4);';
$statement = $connection->prepare($sql); $statement->execute();
$result = $connection->commit();
Expected result:
----------------
I expect the two examples to work exactly the same. In practice this difference is introduced on
versions of PHP which contain commit 51cdd3dc50af88461d83aec0fac1dca83400b58f .
This means 5.6 works the same for both examples. However, 7.0.23, 7.1.9, and 7.2.0 are the releases
that introduce this change in the git tree.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=79872&edit=1
Thread (6 messages)