AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth

3)
Patroni does only failovers. Also in case of regular shutdown of the primary. A failover is a promote of the standby + automatic reinstate (pg_rewind or pg_basebackup) of the former primary.

Time: role site 1 - role site 2
====================
12:00h: primary - standby
=> Some clients commited some transactions; Primary stopped => Failover to standby
12:05h: standby - primary
=> Some clients connected + commited some transactions; Primary stopped => Failover to standby
12:10h: primary - standby

Patroni.yml)
$ cat pcl_l702.yml
scope: pcl_l702
name: pcl_l702(at)tstm49003
namespace: /patroni/

log:
level: DEBUG
dir: /opt/app/patroni/etc/log/
file_num: 10
file_size: 104857600

restapi:
listen: tstm49003.tstglobal.tst.loc:8010
connect_address: tstm49003.tstglobal.tst.loc:8010

etcd:
hosts: etcdlab01.tstglobal.tst.loc:2379,etcdlab02.tstglobal.tst.loc:2379,etcdlab03.tstglobal.tst.loc:2379,etcdlab04.tstglobal.tst.loc:2379,etcdlab05.tstglobal.tst.loc:2379
username: patroni
password: censored

bootstrap:
dcs:
ttl: 30
loop_wait: 10
retry_timeout: 10
maximum_lag_on_failover: 1048576
master_start_timeout: 300
synchronous_mode: true
postgresql:
use_pg_rewind: true
use_slots: true

# NO BOOTSTRAPPING USED
method: do_not_bootstrap
do_not_bootstrap:
command: /bin/false

postgresql:
authentication:
replication:
username: repadmin
password: censored
superuser:
username: patroni
password: censored
callbacks:
on_reload: /opt/app/patroni/etc/callback_patroni.sh
on_restart: /opt/app/patroni/etc/callback_patroni.sh
on_role_change: /opt/app/patroni/etc/callback_patroni.sh
on_start: /opt/app/patroni/etc/callback_patroni.sh
on_stop: /opt/app/patroni/etc/callback_patroni.sh
connect_address: tstm49003.tstglobal.tst.loc:5436
database: pcl_l702
data_dir: /pgdata/pcl_l702
bin_dir: /usr/pgsql-9.6/bin
listen: localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc:5436
pgpass: /home/postgres/.pgpass_patroni
recovery_conf:
restore_command: cp /pgxlog_archive/pcl_l702/%f %p
parameters:
hot_standby_feedback: on
wal_keep_segments: 64
use_pg_rewind: true

watchdog:
mode: automatic
device: /dev/watchdog
safety_margin: 5

tags:
nofailover: false
noloadbalance: false
clonefrom: false
nosync: false

-----Ursprüngliche Nachricht-----
Von: Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
Gesendet: Donnerstag, 7. November 2019 17:06
An: Zwettler Markus (OIZ) <Markus(dot)Zwettler(at)zuerich(dot)ch>; pgsql-general(at)lists(dot)postgresql(dot)org
Betreff: Re: AW: AW: broken backup trail in case of quickly patroni switchback and forth

On 11/7/19 7:47 AM, Zwettler Markus (OIZ) wrote:

I am heading out the door so I will not have time to look at below until later. For those that get a chance before then, it would be nice to have the Patroni conf file information also. The Patroni information may answer the question, but it case it does not what actually is failover in 3) below?

> 1) 9.6
>
>
>
> 2)
> $ cat postgresql.conf
> # Do not edit this file manually!
> # It will be overwritten by Patroni!
> include 'postgresql.base.conf'
>
> cluster_name = 'pcl_l702'
> hot_standby = 'on'
> hot_standby_feedback = 'True'
> listen_addresses = 'localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc'
> max_connections = '100'
> max_locks_per_transaction = '64'
> max_prepared_transactions = '0'
> max_replication_slots = '10'
> max_wal_senders = '10'
> max_worker_processes = '8'
> port = '5436'
> track_commit_timestamp = 'off'
> wal_keep_segments = '8'
> wal_level = 'replica'
> wal_log_hints = 'on'
> hba_file = '/pgdata/pcl_l702/pg_hba.conf'
> ident_file = '/pgdata/pcl_l702/pg_ident.conf'
> $
> $
> $
> $ cat postgresql.base.conf
> datestyle = 'iso, mdy'
> default_text_search_config = 'pg_catalog.english'
> dynamic_shared_memory_type = posix
> lc_messages = 'en_US.UTF-8'
> lc_monetary = 'de_CH.UTF-8'
> lc_numeric = 'de_CH.UTF-8'
> lc_time = 'de_CH.UTF-8'
> logging_collector = on
> log_directory = 'pg_log'
> log_rotation_age = 1d
> log_rotation_size = 0
> log_timezone = 'Europe/Vaduz'
> log_truncate_on_rotation = on
> max_connections = 100
> timezone = 'Europe/Vaduz'
> archive_command = 'test ! -f /tmp/pg_archive_backup_running_on_pcl_l702* && rsync --checksum %p /pgxlog_archive/pcl_l702/%f'
> archive_mode = on
> archive_timeout = 1800
> cluster_name = pcl_l702
> cron.database_name = 'pdb_l72_oiz'
> # effective_cache_size
> listen_addresses = '*'
> log_connections = on
> log_destination = 'stderr, csvlog'
> log_disconnections = on
> log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
> log_line_prefix = '%t : %h=>%u(at)%d : %p-%c-%v : %e '
> log_statement = 'ddl'
> max_wal_senders = 5
> port = 5436
> shared_buffers = 512MB
> shared_preload_libraries = 'auto_explain, pg_stat_statements, pg_cron, pg_statsinfo'
> wal_buffers = 16MB
> wal_compression = on
> wal_level = replica
> # work_mem
>
>
>
> 3)
> 12:00h: primary - standby
> => Some clients commited some transactions; Failover
> 12:05h: standby - primary
> => Some clients connected + commited some transactions; Failover
> 12:10h: primary - standby
>
>
>
>
>
> On 11/7/19 7:18 AM, Zwettler Markus (OIZ) wrote:
>> I already asked the Patroni folks. They told me this is not related
>> to Patroni but Postgresql. ;-)
>
> Hard to say without more information:
>
> 1) Postgres version
>
> 2) Setup/config info
>
> 3) Detail if what happened between 12:00 and 12:10
>
>>
>> - Markus
>>
>>
>>
>> On 11/7/19 5:52 AM, Zwettler Markus (OIZ) wrote:
>>> we are using Patroni for management of our Postgres standby databases.
>>>
>>> we take our (wal) backups on the primary side based on intervals and thresholds.
>>> our archived wal's are written to a local wal directory first and moved to tape afterwards.
>>>
>>> we got a case where Patroni switched back and forth sides quickly, e.g.:
>>> 12:00h: primary - standby
>>> 12:05h: standby - primary
>>> 12:10h: primary - standby
>>>
>>> we realised that we will not have a wal backup of those wal's generated between 12:05h and 12:10h in this scenario.
>>>
>>> how can we make sure that the whole wal sequence trail will be backuped? any idea?
>>
>> Probably best to ask the Patroni folks:
>>
>> https://github.com/zalando/patroni#community
>>
>>>
>>> - Markus
>>>
>>>
>>
>>
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com