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Date: Fri, 15 Nov 2013 06:33:40 +0900
Message-ID: <CAGa2bXZo_z9tmbuX22_vt8QdyOiAw8wmc4LP=PSNLfgubmhS9g@mail.gmail.com>
To: Adam Harvey <aharvey@php.net>
Cc: Stas Malyshev <smalyshev@sugarcrm.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=089e0117720f37464a04eb29d82b
Subject: Re: [PHP-DEV] Session cache, lock and write
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

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Hi Adam and Stas,

On Fri, Nov 15, 2013 at 6:25 AM, Adam Harvey <aharvey@php.net> wrote:

> On 14 November 2013 13:19, Stas Malyshev <smalyshev@sugarcrm.com> wrote:
> >> I think you've wrote this before I sent new mail. For files save
> handler,
> >> when session.lock=3DOff, it will be
> >>
> >> open-and-lock -> read session data -> close-and-unlock ->
> >> script executed
> >> -> open-and-lock -> write session data -> close-and-unlock
> >
> > I don't think this is a very good idea, since what happens if somebody
> > else changed the state while script was executing? That change would be
> > killed by the write. The lock is not for writing, the lock is for data
> > consistency between reading in writing. If you gave up the lock, you
> > should not write afterwards because your data may be stale.
>
> I can see situations where that might be useful =E2=80=94 where it's not =
so
> important if the write gets clobbered so long as there's minimal
> locking to ensure that the session file is at least valid.
>
> I'm still on the fence about whether it's actually a useful thing to
> support in php-src, though. It might be enough of a corner case to not
> make it worth supporting in a bundled session handler, and I'm worried
> the people might start giving advice that using it will "speed up your
> application" and users who copy-paste configurations will silently
> usedata.
>
> As an aside, if we do implement it: Yasuo, you've convinced me that
> session.lock is a reasonable name (instead of being handler-specific).
> :)


Memcached/Memcache/MongoDB session save handlers already have
lock option.

I think not few users are used to it already.

Regards,

--
Yasuo Ohgaki
yohgaki@ohgaki.net

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