Re: [EXTERNAL]Re: pg_dump -Fd -j2 on standby in 9.6.6

[David G. Johnston]

On Wed, Mar 28, 2018 at 10:13 AM, Ron  wrote:

> On 03/28/2018 03:05 AM, Andreas Kretschmer wrote:
> [snip]
>
>> > This e-mail message, including any attachments,
>>
>> this is a public mailing list ...
>>
>
> The intended recipient is the public mailing list, no?


​A mailing list doesn't really "receive" email - it is only a distribution
mechanism.  IANAL but basically adding boilerplate like that to mail sent
to a public mailing list is pointless - there are no "intended recipients"
but rather the message is being put into the public domain for anyone to
consume, regardless of whether they are/were a member of the mailing list
to which the email was addressed.

David J.

Re: [EXTERNAL]Re: pg_dump -Fd -j2 on standby in 9.6.6

[Ron]

On 03/28/2018 03:05 AM, Andreas Kretschmer wrote:
[snip]

> This e-mail message, including any attachments,

this is a public mailing list ...


The intended recipient is the public mailing list, no?

--
Angular momentum makes the world go 'round.

Re: [EXTERNAL]Re: pg_dump -Fd -j2 on standby in 9.6.6

[Andreas Kretschmer]

Am 28.03.2018 um 09:46 schrieb Stefan Petrea:

Hi Andreas,

Thank you for your suggestion about pausing/resuming the standby!

I've tried running on the standby
SELECT pg_xlog_replay_pause()
Then running the dump, and it threw the same error I had seen before.


run pg_dump with --no-synchronized-snapshots, it is save in this szenario.

> This e-mail message, including any attachments,

this is a public mailing list ...


Regards, Andreas
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2ndQuadrant - The PostgreSQL Support Company.
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RE: [EXTERNAL]Re: pg_dump -Fd -j2 on standby in 9.6.6

[Stefan Petrea]

Hi Andreas,

Thank you for your suggestion about pausing/resuming the standby!

I've tried running on the standby
SELECT pg_xlog_replay_pause()
Then running the dump, and it threw the same error I had seen before.
Seeing that I wasn't able to do it, I just ran 
SELECT pg_xlog_replay_resume()
On the slave.

I've asked in the IRC channel as well and I've been told that in version 10
this would work on standbys. I've looked at the code [3]
and indeed it does not have the check for standby anymore (as it did in the 
previous
gdb code listing in my initial email).

But.. upgrading to 10 would be quite a heavy thing for now, since it would 
involve many changes 
so I don't believe that would be feasible right now.

[3] 
https://github.com/postgres/postgres/blob/REL_10_STABLE/src/bin/pg_dump/pg_dump.c#L1149

Stefan Petrea
System Engineer/DBA, Network Engineering


stefan.pet...@tangoe.com 

     

tangoe.com



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-Original Message-
From: Andreas Kretschmer [mailto:andr...@a-kretschmer.de] 
Sent: Wednesday, March 28, 2018 8:26 AM
To: pgsql-general@lists.postgresql.org; Stefan Petrea 
<stefan.pet...@tangoe.com>; pgsql-gene...@postgresql.org
Subject: [EXTERNAL]Re: pg_dump -Fd -j2 on standby in 9.6.6

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On 28 March 2018 07:02:30 CEST, Stefan Petrea <stefan.pet...@tangoe.com> wrote:
>Hi,
>
>
>I wonder why synchronized snapshots are not supported on standby 
>servers.
>
>
>
If you want to take backups using -Fd on a standby you should pause the 
reply-process. In this case you don' t need synchronized snapshots.

Regards, Andreas.


--
2ndQuadrant - The PostgreSQL Support Company