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[RFC] [Discussion] Minimum supported versions for PHP 8.6

php.internals

Eric Norris

61 days ago

Hey all,

I hope you've been enjoying what appears to be the RFC "busy season".
I've got another RFC following up on an earlier thread about adding
COM_RESET_CONNECTION support to PDO and mysqlnd:

https://wiki.php.net/rfc/min_supported_versions_php_8_6

This proposes a minimum version requirement for autoconf when building
from source, and a minimum version requirement of MySQL 5.7.3 and
MariaDB 10.2.4 when using persistent connections.

- Original thread: https://news-web.php.net/php.internals/130704
- autoconf PR: https://github.com/php/php-src/pull/21159
- COM_RESET_CONNECTION PR: https://github.com/php/php-src/pull/21857
and original issue: https://github.com/php/php-src/issues/20225

(Tim, I've not added you as an author since I wasn't sure you'd be
cool with that, but if you'd like I would be more than happy to.)

Thank you,
Eric Norris

Tim Düsterhus

61 days ago

Hi

Am 2026-07-02 16:53, schrieb Eric Norris:

> (Tim, I've not added you as an author since I wasn't sure you'd be
> cool with that, but if you'd like I would be more than happy to.)

I'm okay with that.

------

And with regard to the RFC itself: Leaving the “Open Issues” and “Future
Scope” sections empty looks weird. I suggest to either remove them
completely or insert an explicit “None” or so. The same is true for the
SAPI impact. The changelog could just be an "- 2026-07-02: Initial
version" and then "- 2026-07-02: Clarify impact" (see below).

The “References” section should ideally include links to the Pre-RFC
discussion thread and must include a link to this discussion. For your
convenience: https://news-web.php.net/php.internals/131707 +
https://news-web.php.net/php.internals/130704).

An “ecosystem impact” of “None” is also almost always wrong. I would
mention the following (perhaps with a little nicer phrasing).

- For COM_RESET_CONNECTION: The proper reset on persistent connections
has the (positive) impact that the behavior of persistent connections
will be more predictable. Of course if folks rely on some connection
state carrying over across requests, they might see a breaking change.
- Users that want to use the newest PHP version will be required to also
run newer versions (released in the last 5 years) of other software.

Best regards
Tim Düsterhus

Eric Norris

61 days ago

On Thu, Jul 2, 2026 at 11:09 AM Tim Düsterhus <tim@bastelstu.be> wrote:

>
> Hi
>
> Am 2026-07-02 16:53, schrieb Eric Norris:
> > (Tim, I've not added you as an author since I wasn't sure you'd be
> > cool with that, but if you'd like I would be more than happy to.)
>
> I'm okay with that.
>
> ------
>
> And with regard to the RFC itself: Leaving the “Open Issues” and “Future
> Scope” sections empty looks weird. I suggest to either remove them
> completely or insert an explicit “None” or so. The same is true for the
> SAPI impact. The changelog could just be an "- 2026-07-02: Initial
> version" and then "- 2026-07-02: Clarify impact" (see below).
>
> The “References” section should ideally include links to the Pre-RFC
> discussion thread and must include a link to this discussion. For your
> convenience: https://news-web.php.net/php.internals/131707 +
> https://news-web.php.net/php.internals/130704).
>
> An “ecosystem impact” of “None” is also almost always wrong. I would
> mention the following (perhaps with a little nicer phrasing).
>
> - For COM_RESET_CONNECTION: The proper reset on persistent connections
> has the (positive) impact that the behavior of persistent connections
> will be more predictable. Of course if folks rely on some connection
> state carrying over across requests, they might see a breaking change.
> - Users that want to use the newest PHP version will be required to also
> run newer versions (released in the last 5 years) of other software.
>
> Best regards
> Tim Düsterhus

Thank you, I've both added you as an author and included your
suggested changes, with slight edits.

Tim Düsterhus

61 days ago

Hi

Am 2026-07-02 17:48, schrieb Eric Norris:

> Thank you, I've both added you as an author and included your
> suggested changes, with slight edits.

Thank you. No further remarks from my side.

Best regards
Tim Düsterhus

Unnamed Person

61 days ago

> Users that are on MySQL or MariaDB databases from before this feature was implemented may upgrade to PHP 8.6, but would not be able to use persistent connections. This means that their software could continue to work, but they might lose a performance optimization.

Please clarify this.
Users on older mysql will hit connection error immediately after
upgrading to 8.6. So saying "their software could continue to work" is
misleading. Their PHP code must be modified before upgrading - turning
PDO::ATTR_PERSISTENT to false or removing it entirely. And only after
that it would continue to work.

Eric Norris

61 days ago

On Thu, Jul 2, 2026 at 11:42 AM <go.al.ni@gmail.com> wrote:

>
> > Users that are on MySQL or MariaDB databases from before this feature was implemented may upgrade to PHP 8.6, but would not be able to use persistent connections. This means that their software could continue to work, but they might lose a performance optimization.
>
> Please clarify this.
> Users on older mysql will hit connection error immediately after
> upgrading to 8.6. So saying "their software could continue to work" is
> misleading. Their PHP code must be modified before upgrading - turning
> PDO::ATTR_PERSISTENT to false or removing it entirely. And only after
> that it would continue to work.

Is this true? Having looked at the persistent connection code, I
believe it would silently handle the error by simply discarding the
connection and creating a new one. Thus, "their software could
continue to work, but they might lose a performance optimization."

Source: https://github.com/php/php-src/pull/21857/files#diff-9a6d6a4359a98668fef29400492f877938424d1b1d2e84933c91ab34161cf360R417-R428

Unnamed Person

60 days ago

> Is this true?

It's not true. Sorry about that. Script didn't crash.

But something worse happened.

I took sources from
https://github.com/ericnorris/php-src/archive/refs/heads/feat-mysqlnd-com-reset-connection.zip
Configured them with `--enable-mysqlnd --enable-fpm
--with-fpm-user=www-data --with-fpm-group=www-data --enable-pdo
--with-pdo-mysql=mysqlnd`
Up mysql 5.5.61.
Started php-fpm with `pm = static` and `pm.max_children = 1`.
Ran this script:

```php
<?php
$pdo = new PDO('mysql:host=172.17.0.1', 'root', '',
[PDO::ATTR_PERSISTENT => true]);
$q = $pdo->query('SHOW PROCESSLIST');
$rows = 0;
while ($f = $q->fetch(PDO::FETCH_ASSOC)) {
$rows++;
}
echo $rows . PHP_EOL;
```

On the first execution script echoes 1. On the second - 2. Each
execution increments the counter by one. When I restart the php-fpm
process, the counter restarts again from 1. There is connection leak
here!

When I removed `PDO::ATTR_PERSISTENT`, the counter stop increasing.
When I switched to mysql 8, counter was always 1 (both with and
without persistent connections).

Eric Norris

60 days ago

On Fri, Jul 3, 2026 at 7:32 AM <go.al.ni@gmail.com> wrote:

>
> > Is this true?
>
> It's not true. Sorry about that. Script didn't crash.
>
> But something worse happened.
>
> I took sources from
> https://github.com/ericnorris/php-src/archive/refs/heads/feat-mysqlnd-com-reset-connection.zip
> Configured them with `--enable-mysqlnd --enable-fpm
> --with-fpm-user=www-data --with-fpm-group=www-data --enable-pdo
> --with-pdo-mysql=mysqlnd`
> Up mysql 5.5.61.
> Started php-fpm with `pm = static` and `pm.max_children = 1`.
> Ran this script:
>
> ```php
> <?php
> $pdo = new PDO('mysql:host=172.17.0.1', 'root', '',
> [PDO::ATTR_PERSISTENT => true]);
> $q = $pdo->query('SHOW PROCESSLIST');
> $rows = 0;
> while ($f = $q->fetch(PDO::FETCH_ASSOC)) {
>   $rows++;
> }
> echo $rows . PHP_EOL;
> ```
>
> On the first execution script echoes 1. On the second - 2. Each
> execution increments the counter by one. When I restart the php-fpm
> process, the counter restarts again from 1. There is connection leak
> here!
>
> When I removed `PDO::ATTR_PERSISTENT`, the counter stop increasing.
> When I switched to mysql 8, counter was always 1 (both with and
> without persistent connections).

Thank you for identifying a connection leak; I have identified the
cause and I'm considering how to address it. That said, I don't
believe this is inherent to the RFC, instead I would consider this a
bug in my implementation.

Eric Norris

54 days ago

On Thu, Jul 2, 2026 at 10:53 AM Eric Norris <eric.t.norris@gmail.com> wrote:

>
> Hey all,
>
> I hope you've been enjoying what appears to be the RFC "busy season".
> I've got another RFC following up on an earlier thread about adding
> COM_RESET_CONNECTION support to PDO and mysqlnd:
>
> https://wiki.php.net/rfc/min_supported_versions_php_8_6
>
> This proposes a minimum version requirement for autoconf when building
> from source, and a minimum version requirement of MySQL 5.7.3 and
> MariaDB 10.2.4 when using persistent connections.
>
> - Original thread: https://news-web.php.net/php.internals/130704
> - autoconf PR: https://github.com/php/php-src/pull/21159
> - COM_RESET_CONNECTION PR: https://github.com/php/php-src/pull/21857
> and original issue: https://github.com/php/php-src/issues/20225
>
> (Tim, I've not added you as an author since I wasn't sure you'd be
> cool with that, but if you'd like I would be more than happy to.)
>
> Thank you,
> Eric Norris

I know there are a lot of other RFCs going around, so I'm sending this
intent to vote message at the earliest possible time as permitted by
the RFC policy. I intend to open a vote in 7 days on July 16th,
exactly 14 days after my initial message (and the last changes to the
RFC). Please take a look if you haven't already.

Thanks!