Re: Introduce XID age and inactive timeout based replication slot invalidation

Поиск
Список
Период
Сортировка
От Amit Kapila
Тема Re: Introduce XID age and inactive timeout based replication slot invalidation
Дата
Msg-id CAA4eK1+2mJgi1q0Chfh4NbQ+M6W4OXWGbYHwM4C2SpfGp5aUfw@mail.gmail.com
обсуждение исходный текст
Ответ на Re: Introduce XID age and inactive timeout based replication slot invalidation  (Bertrand Drouvot <bertranddrouvot.pg@gmail.com>)
Ответы Re: Introduce XID age and inactive timeout based replication slot invalidation  (Bertrand Drouvot <bertranddrouvot.pg@gmail.com>)
Список pgsql-hackers
On Fri, Mar 22, 2024 at 3:15 PM Bertrand Drouvot
<bertranddrouvot.pg@gmail.com> wrote:
>
> On Fri, Mar 22, 2024 at 01:45:01PM +0530, Bharath Rupireddy wrote:
>
> 1 ===
>
> @@ -691,6 +699,13 @@ ReplicationSlotRelease(void)
>                 ConditionVariableBroadcast(&slot->active_cv);
>         }
>
> +       if (slot->data.persistency == RS_PERSISTENT)
> +       {
> +               SpinLockAcquire(&slot->mutex);
> +               slot->last_inactive_at = GetCurrentTimestamp();
> +               SpinLockRelease(&slot->mutex);
> +       }
>
> I'm not sure we should do system calls while we're holding a spinlock.
> Assign a variable before?
>
> 2 ===
>
> Also, what about moving this here?
>
> "
>     if (slot->data.persistency == RS_PERSISTENT)
>     {
>         /*
>          * Mark persistent slot inactive.  We're not freeing it, just
>          * disconnecting, but wake up others that may be waiting for it.
>          */
>         SpinLockAcquire(&slot->mutex);
>         slot->active_pid = 0;
>         SpinLockRelease(&slot->mutex);
>         ConditionVariableBroadcast(&slot->active_cv);
>     }
> "
>
> That would avoid testing twice "slot->data.persistency == RS_PERSISTENT".
>

That sounds like a good idea. Also, don't we need to consider physical
slots where we don't reserve WAL during slot creation? I don't think
there is a need to set inactive_at for such slots. If we agree,
probably checking restart_lsn should suffice the need to know whether
the WAL is reserved or not.

>
> 5 ===
>
> Most of the fields that reflect a time (not duration) in the system views are
> xxxx_time, so I'm wondering if instead of "last_inactive_at" we should use
> something like "last_inactive_time"?
>

How about naming it as last_active_time? This will indicate the time
at which the slot was last active.

--
With Regards,
Amit Kapila.



В списке pgsql-hackers по дате отправления:

Предыдущее
От: Alexander Pyhalov
Дата:
Сообщение: Re: ExecAppendAsyncEventWait() in REL_14_STABLE can corrupt PG_exception_stack
Следующее
От: Maxim Orlov
Дата:
Сообщение: Re: Refactoring of pg_resetwal/t/001_basic.pl