Re: Online base backup from the hot-standby

From: Jun Ishiduka <ishizuka(dot)jun(at)po(dot)ntts(dot)co(dot)jp>
To: masao(dot)fujii(at)gmail(dot)com
Cc: ssinger_pg(at)sympatico(dot)ca, simon(at)2ndquadrant(dot)com, pgsql-hackers(at)postgresql(dot)org, magnus(at)hagander(dot)net, robertmhaas(at)gmail(dot)com, cedric(dot)villemain(dot)debian(at)gmail(dot)com, heikki(dot)linnakangas(at)enterprisedb(dot)com
Subject: Re: Online base backup from the hot-standby
Date: 2011-10-19 02:47:08
Message-ID: 201110190248.p9J2mSf7018918@ccmds32.silk.ntts.co.jp
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> > + /*
> > + * The backend writes WAL of FPW at checkpoint. However, The backend do
> > + * not need to write WAL of FPW at checkpoint shutdown because it
> > + * performs when startup finishes.
> > + */
> > + XLogReportParameters(REPORT_ON_BACKEND);
> >
> > I'm still unclear why that WAL doesn't need to be written at shutdown
> > checkpoint.
> > Anyway, the first sentence in the above comments is not right. Not a backend but
> > a bgwriter writes that WAL at checkpoint.
> >
> > The second also seems not to be right. It implies that a shutdown checkpoint is
> > performed only at end of startup. But it may be done when smart or fast shutdown
> > is requested.
>
>
> Okay.
> I change to the following messages.
>
> /*
> * The bgwriter writes WAL of FPW at checkpoint. But does not at shutdown.
> * Because XLogReportParameters() is always called at the end of startup
> * process, it does not need to be called at shutdown.
> */
>
>
> In addition, I change macro name.
>
> REPORT_ON_BACKEND -> REPORT_ON_BGWRITER

I have updated as above-comment.
Please check this.

Regards.

--------------------------------------------
Jun Ishizuka
NTT Software Corporation
TEL:045-317-7018
E-Mail: ishizuka(dot)jun(at)po(dot)ntts(dot)co(dot)jp
--------------------------------------------

Attachment Content-Type Size
standby_online_backup_09base-06fpw.patch application/octet-stream 14.3 KB

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