Re: Is Recovery actually paused?

On Fri, Feb 5, 2021 at 10:06 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Fri, Feb 5, 2021 at 6:22 AM Bharath Rupireddy
> <bharath.rupireddyforpostgres@gmail.com> wrote:
> >
> > On Thu, Feb 4, 2021 at 7:20 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > > > How can we do that this is not a 1 byte flag this is enum so I don't
> > > > think we can read any atomic state without a spin lock here.
> > >
> > > I have fixed the other comments and the updated patch is attached.
> >
> > Can we just do like below so that we could use the existing
> > SetRecoveryPause instead of setting the state outside?
> >
> >     /* loop until recoveryPauseState is set to RECOVERY_NOT_PAUSED */
> >     while (1)
> >     {
> >         RecoveryPauseState state;
> >
> >         state = GetRecoveryPauseState();
> >
> >         if (state == RECOVERY_NOT_PAUSED)
> >             break;
> >
> >         HandleStartupProcInterrupts();
> >
> >         if (CheckForStandbyTrigger())
> >             return;
> >         pgstat_report_wait_start(WAIT_EVENT_RECOVERY_PAUSE);
> >
> >         /*
> >          * If recovery pause is requested then set it paused.  While we are in
> >          * the loop, user might resume and pause again so set this every time.
> >          */
> >         if (state == RECOVERY_PAUSE_REQUESTED)
> >             SetRecoveryPause(RECOVERY_PAUSED)
>
> We can not do that, basically, under one lock we need to check the
> state and set it to pause.  Because by the time you release the lock
> someone might set it to RECOVERY_NOT_PAUSED then you don't want to set
> it to RECOVERY_PAUSED.

Got it. Thanks.

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com