Re: Multiplexing SUGUSR1 - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Multiplexing SUGUSR1
Date
Msg-id 493E80BE.2070000@enterprisedb.com
Whole thread Raw
In response to Re: Multiplexing SUGUSR1  ("Fujii Masao" <masao.fujii@gmail.com>)
Responses Re: Multiplexing SUGUSR1
List pgsql-hackers
Fujii Masao wrote:
> Hi,
> 
> On Mon, Dec 8, 2008 at 11:39 PM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
>> Tom Lane wrote:
>>> Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
>>>> To set or clear the flag from PGPROC, to send or handle a signal, we have
>>>> to acquire ProcArrayLock. Is that safe to do in a signal handler?
>>> No.  If it's trying to do that then it's broken.  In fact, if it's
>>> trying to do much of anything beyond setting a "volatile" flag variable
>>> in a signal handler, it's broken --- unless there are special provisions
>>> to limit where the signal trap can occur, which would be pretty much
>>> unacceptable for a multiplexed-signal implementation.
>> Ok, I was afraid so.
>>
>> I think we'll need to replace the proposed bitmask with an array of
>> sig_atomic_t flags then, and do without locking.
> 
> Thanks! I updated the patch so (based on signal_handling_v2-heikki-1.patch).

Thank you. Looks good to me, committed with minor changes.

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


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