From: | James Sewell <james(dot)sewell(at)lisasoft(dot)com> |
---|---|
To: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Streaming replication and an archivelog |
Date: | 2015-05-08 07:17:21 |
Message-ID: | CANkGpBvUDRpFNXDtO22ueUeYZLgMuJ6Dhr2vA8mi8x90QDpyEw@mail.gmail.com |
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Lists: | pgsql-general |
OK I think I have a solution, using the following script as the
restore_command
echo $1 | grep history > /dev/null
if [ $? -eq 0 ]; then
exit 1
fi
scp postgres(at)postgres3:/archived_wals/$1 $2
This seems to work, as it restricts slave servers from switching timeline
from the archive by stopping them ever knowing about history files.
Can anyone see any problems with this approach?
Cheers,
James Sewell,
PostgreSQL Team Lead / Solutions Architect
______________________________________
Level 2, 50 Queen St, Melbourne VIC 3000
*P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099
On Fri, May 8, 2015 at 4:47 PM, James Sewell <james(dot)sewell(at)lisasoft(dot)com>
wrote:
> Hey,
>
> This is an example of what I see when starting up a replica and attaching
> it to a master.
>
> In this case the master is in timeline 3, but the archive log goes up to
> timeline 6.
>
> 2015-05-08 16:23:07 AEST @ ( 0 00000)LOG: database system was
> interrupted; last known up at 2015-05-08 16:21:14 AEST
> 2015-05-08 16:23:07 AEST @ ( 0 00000)LOG: restored log file
> "00000004.history" from archive
> 2015-05-08 16:23:08 AEST @ ( 0 00000)LOG: restored log file
> "00000005.history" from archive
> 2015-05-08 16:23:08 AEST @ ( 0 00000)LOG: restored log file
> "00000006.history" from archive
> scp: /backup/production/archived_wals/00000007.history: No such file or
> directory
> 2015-05-08 16:23:08 AEST @ ( 0 00000)LOG: entering standby mode
> 2015-05-08 16:23:09 AEST @ ( 0 00000)LOG: restored log file
> "00000006.history" from archive
> scp: /backup/production/archived_wals/000000060000000B000000C2: No such
> file or directory
> scp: /backup/production/archived_wals/000000050000000B000000C2: No such
> file or directory
> scp: /backup/production/archived_wals/000000040000000B000000C2: No such
> file or directory
> 2015-05-08 16:23:11 AEST @ ( 0 00000)LOG: restored log file
> "000000030000000B000000C2" from archive
> 2015-05-08 16:23:11 AEST @ ( 0 XX000)FATAL: requested timeline 6 is not a
> child of this server's history
> 2015-05-08 16:23:11 AEST @ ( 0 XX000)DETAIL: Latest checkpoint is at
> B/C2000060 on timeline 3, but in the history of the requested timeline, the
> server forked off from that timeline at B/BE000060.
> 2015-05-08 16:23:11 AEST @ ( 0 00000)LOG: startup process (PID 21893)
> exited with exit code 1
> 2015-05-08 16:23:11 AEST @ ( 0 00000)LOG: aborting startup due to startup
> process failure
>
>
> Cheers,
>
>
> James Sewell,
> PostgreSQL Team Lead / Solutions Architect
> ______________________________________
>
>
> Level 2, 50 Queen St, Melbourne VIC 3000
>
> *P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099
>
>
> On Fri, May 8, 2015 at 4:28 PM, James Sewell <james(dot)sewell(at)lisasoft(dot)com>
> wrote:
>
>> Hello All,
>>
>> I am running 9.4 on Centos.
>>
>> I have three servers, one master and two slaves. The slaves have the
>> following recovery.conf
>>
>> standby_mode = 'on'
>> primary_conninfo = 'user=postgres host=mastervip port=5432'
>> restore_command = 'scp -o BatchMode=yes postgres(at)backuphost:/archived_wals/%f
>> %p'
>> recovery_target_timeline= 'latest'
>>
>> Is there any way to combine following
>>
>> - a master switch (ie: if node1 dies and node2 is promoted then node3
>> follows node2)
>> - using a WAL archive, such that if node2 goes down for two days it
>> will get WALs from the archive if they are no longer on the master
>>
>> At the moment the master switch works fine, but if I was to have a WAL
>> archive with multiple timelines in it then I would end up in the newest
>> timeline.
>>
>> I suppose what I want is the following:
>>
>> If I am a streaming replica only follow streamed timeline switches, not
>> archive timeline switches.
>>
>> Obviously if I am not a streaming replica I need to follow archive
>> timeline switches so I don't break PIT recovery.
>>
>> Possible?
>>
>>
>> James Sewell,
>> PostgreSQL Team Lead / Solutions Architect
>> ______________________________________
>>
>>
>> Level 2, 50 Queen St, Melbourne VIC 3000
>>
>> *P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099
>>
>>
>
>
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