Re: [Patch] ALTER SYSTEM READ ONLY - Mailing list pgsql-hackers

From Dilip Kumar
Subject Re: [Patch] ALTER SYSTEM READ ONLY
Date
Msg-id CAFiTN-tjwhLs00nvpcEKW1RfZTvk-UG+FvRRbz+kzfXNMm1mEw@mail.gmail.com
Whole thread Raw
In response to Re: [Patch] ALTER SYSTEM READ ONLY  (Amul Sul <sulamul@gmail.com>)
Responses Re: [Patch] ALTER SYSTEM READ ONLY
List pgsql-hackers
On Thu, May 13, 2021 at 2:54 PM Amul Sul <sulamul@gmail.com> wrote:
>
> On Thu, May 13, 2021 at 12:36 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > On Wed, May 12, 2021 at 5:55 PM Amul Sul <sulamul@gmail.com> wrote:
> > >
> >
> > Thanks for the updated patch, while going through I noticed this comment.
> >
> > + /*
> > + * WAL prohibit state changes not allowed during recovery except the crash
> > + * recovery case.
> > + */
> > + PreventCommandDuringRecovery("pg_prohibit_wal()");
> >
> > Why do we need to allow state change during recovery?  Do you still
> > need it after the latest changes you discussed here, I mean now
> > XLogAcceptWrites() being called before sending barrier to backends.
> > So now we are not afraid that the backend will write WAL before we
> > call XLogAcceptWrites().  So now IMHO, we don't need to keep the
> > system in recovery until pg_prohibit_wal(false) is called, right?
> >
>
> Your understanding is correct, and the previous patch also does the same, but
> the code comment is wrong.  Fixed in the attached version, also rebased for the
> latest master head. Sorry for the confusion.

Great thanks.  I will review the remaining patch soon.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com



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