Обсуждение: elog during holding a spinlock is safe?

Hi,

In HEAD, OwnLatch can elog during holding the spinlock WalSnd->mutex.
This seems to be unsafe because that elog would cause the walsender
to exit without releasing the spinlock. Because of the spinlock being
held, subsequent walsender would get stuck. I wonder if OwnLatch really
needs to be protected by the spinlock.

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center

Fujii Masao <masao.fujii@gmail.com> writes:
> In HEAD, OwnLatch can elog during holding the spinlock WalSnd->mutex.
> This seems to be unsafe

Even if it were safe, holding a spinlock through non-straight-line code
is a complete violation of the spinlock coding rules re the length of
time you're supposed to hold the lock.  Heikki?
        regards, tom lane

On 15/09/10 05:47, Tom Lane wrote:
> Fujii Masao<masao.fujii@gmail.com>  writes:
>> In HEAD, OwnLatch can elog during holding the spinlock WalSnd->mutex.
>> This seems to be unsafe
>
> Even if it were safe, holding a spinlock through non-straight-line code
> is a complete violation of the spinlock coding rules re the length of
> time you're supposed to hold the lock.  Heikki?

Yep, that's an oversight. I'll move the OwnLatch call after the spinlock 
is released.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com