Re: Re: [COMMITTERS] pgsql: Map basebackup tablespaces using a tablespace_map file

From: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Re: [COMMITTERS] pgsql: Map basebackup tablespaces using a tablespace_map file
Date: 2015-09-09 13:13:04
Message-ID: CAHGQGwE1D_JD7Uc7ny_9ScaMn8VQf2uL6YZ2v_FsTi2J7oZmAg@mail.gmail.com
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On Fri, Sep 4, 2015 at 4:48 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Thu, Sep 3, 2015 at 6:07 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>>
>> On Tue, Aug 4, 2015 at 12:15 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
>> wrote:
>> > On Mon, Aug 3, 2015 at 7:44 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
>> > wrote:
>> >> ISTM that we can
>> >> see that the online backup mode has already been canceled if
>> >> backup_label
>> >> file
>> >> is successfully removed whether tablespace_map file remains or not. No?
>> >>
>> >
>> > I think what we should do is that display successful cancellation
>> > message
>> > only when both the files are renamed.
>>
>> Please imagine the case where backup_label was successfully renamed
>> but tablespace_map was not. Even in this case, I think that we can see
>> that the backup mode was canceled because the remaining tablespace_map
>> file will be ignored in the subsequent recovery.
>
> Right.
>
>>
>> So we should emit
>> the successful cancellation message when backup_label is renamed
>> whether tablespace_map is successfully renamed or not?
>>
>
> You mean to say, just try renaming tablespace_map and don't display any
> message whether that is successful or not-successful?
>
> I see some user inconvenience if we do this way, which is even after the
> backup is cancelled, on next recovery, there will be a log message
> indicating
> either rename of tablespace_map successful or unsuccessful. Also, don't you
> think it is better to let user know that the tablespace_map file is
> successfully
> renamed as we do for backup_label file. Shall we change the patch such that
> if backup_label is successfully renamed and renaming of tablespace_map
> gets failed, then display a log message to something like below:
>
> LOG: online backup mode canceled
> DETAIL: "backup_label" was renamed to "backup_label.old", could not rename
> "tablespace_map" to "tablespace_map.old"

Agreed with this direction. So what about the attached patch?

Regards,

--
Fujii Masao

Attachment Content-Type Size
improve_cancelbackup_messages_v1.patch text/x-patch 2.3 KB

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