Edit report at https://bugs.php.net/bug.php?id=80260&edit=1
ID: 80260
Comment by: corey dot taylor dot fl at gmail dot com
Reported by: corey dot taylor dot fl at gmail dot com
Summary: PDO::inTransaction() returns false when inside
transaction
Status: Open
Type: Bug
Package: PDO MySQL
PHP Version: 8.0.0RC2
Block user comment: N
Private report: N
New Comment:
If this turns out to be *entirely* due to DDL transactions - are you saying that
PDO::inTransaction() won't support them?
Previous Comments:
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[2020-10-20 08:50:46] corey dot taylor dot fl at gmail dot com
I spent some time trying to narrow down the scenarios as you mentioned. It's difficult when it
happens in a complex test harness.
Yes, the initial failure were showing up from a DDL transaction. I thought the same thing here that
maybe there was a sync issue. However, the mysql instance clearly thinks the transaction is ok since
it's waiting on a commit.
After working on moving the DDL that fails out of the transactions and only putting inserts into the
transaction, that initial failure stopped, but the same error occurs further down our test suite. It
is possible there is a completely unrelated transaction with DDL in it before this failure, but so
far I haven't found it. The test suite really only runs DDL in one place.
We don't mix manual and PDO transactions. Everything be through beginTransaction, commit and
rollback.
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[2020-10-20 08:44:02] nikic@php.net
Okay, next guess: You are running a DDL query inside a transaction, which (for MySQL) will cause an
automatic commit, even outside autocommit mode
(https://dev.mysql.com/doc/refman/8.0/en/implicit-commit.html). That means inTransaction() reports
false, but PDO still thinks its inside a transaction.
Does that sound plausible?
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[2020-10-20 08:40:02] nikic@php.net
Do you mix usage of PDO transaction APIs with transaction queries? Like, call
PDO::beginTransaction() and then issue a manual COMMIT?
PDO's internal state could go out of sync in such a case. We should probably make PDO
internally use the same mechanism as PDO::inTransaction() to determine whether it is inside a
transaction.
However, I'm not sure this is really the case you're seeing, I suspect that is another
problem here.
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[2020-10-20 03:58:18] corey dot taylor dot fl at gmail dot com
The environment we see this on is ubuntu 16.04 (xenial) travis-ci with default mysql 5.7 and php
nightly builds. There are no custom pdo configurations.
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[2020-10-20 03:36:46] corey dot taylor dot fl at gmail dot com
Description:
------------
We started seeing failures with php 8 and mysql 5.7 that seem to suggest PDO::inTransaction() is
returning false when inside a transaction.
When calling PDO::beginTransaction(), sometimes we see this error:
PDOException: There is already an active transaction
This happens because we skip calling PDO::commit() if PDO::inTransaction() returns false. When
skipping this check and calling commit(), the transaction succeeds. Normally, when that check
returns false, commit() will fail.
I see that inTransaction() for mysql was re-written recently in this commit:
https://github.com/php/php-src/commit/6a4eeb1c47c46d8f6a1c43eb7de8e6ee8158ec99
We're not sure how to find the root cause of this. The test case in the commit checks all ways
to manually start/stop a transaction, but we obviously have other queries in the transaction.
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Edit this bug report at https://bugs.php.net/bug.php?id=80260&edit=1