Re: Return of the pg_wal issue..

Hi Saul,

Fantastic, highly appreciate that.
Initially i've taken the top bit of Laurenz's post to understand what
these wal files are.
Any help is more than welcome, apologies for not checking that bit earlier.
In the meantime i've checked those queries as well.

Thank you

On Thu, Jan 23, 2025 at 2:27 PM Saul Perdomo <saul(dot)perdomo(at)gmail(dot)com> wrote:

> Hey Paul,
>
> Regarding
>
> *"I've not managed to test the queries out yet. But I am planning to test
> out in my lab environment.*
> *Sorry am really cautious about this as those are the main production
> databases."*
>
> As a dispassionate third-party observer, I can confirm that all SELECT and
> SHOW queries from Laurenz's blog post are read-only. They're completely
> safe to run in the affected environment.
>
> On Thu, Jan 23, 2025 at 6:40 AM Paul Brindusa <paulbrindusa88(at)gmail(dot)com>
> wrote:
>
>> Hopefully the below is going to give a little bit more insight on the
>> issue.
>> I will mention as well that the cluster also replicates data to another
>> mysql database if it's relevant at all.
>> Also worth noting this is our production cluster and we have another
>> pre-production cluster with basically the same settings and the issue there
>> does not occur.
>>
>> A good deal more information is needed to troubleshoot this:
>>
>> 1) Postgres version(s).
>>
>> postgres (PostgreSQL) 15.10
>>
>> 2) The Patroni version.
>>
>> patroni 4.0.4
>>
>> 3) The Patroni configuration.
>>
>> scope: postgres-cluster
>> name: db01
>> namespace: /service/
>>
>> log:
>> level: INFO
>> traceback_level: ERROR
>> format: "%(asctime)s %(levelname)s: %(message)s"
>> dateformat: ""
>> max_queue_size: 1000
>> dir: /var/log/patroni
>> file_num: 4
>> file_size: 25000000
>> loggers:
>> patroni.postmaster: WARNING
>> urllib3: WARNING
>>
>> restapi:
>> listen: x.x.x.98:8008
>> connect_address: x.x.x.98:8008
>>
>> etcd3:
>> hosts: db01.local:2379,db02.local:2379,db03.local:2379
>>
>>
>> bootstrap:
>> dcs:
>> ttl: 30
>> loop_wait: 10
>> retry_timeout: 10
>> maximum_lag_on_failover: 1048576
>> postgresql:
>> use_pg_rewind: true
>> use_slots: true
>> parameters:
>> max_connections: 500
>> superuser_reserved_connections: 5
>> password_encryption: scram-sha-256
>> max_locks_per_transaction: 512
>> max_prepared_transactions: 0
>> huge_pages: try
>> shared_buffers: 128MB
>> effective_cache_size: 4GB
>> work_mem: 128MB
>> maintenance_work_mem: 256MB
>> checkpoint_timeout: 15min
>> checkpoint_completion_target: 0.9
>> min_wal_size: 80MB
>> max_wal_size: 1GB
>> wal_buffers: 32MB
>> default_statistics_target: 1000
>> seq_page_cost: 1
>> random_page_cost: 4
>> effective_io_concurrency: 2
>> synchronous_commit: on
>> autovacuum: on
>> autovacuum_max_workers: 5
>> autovacuum_vacuum_scale_factor: 0.01
>> autovacuum_analyze_scale_factor: 0.01
>> autovacuum_vacuum_cost_limit: 500
>> autovacuum_vacuum_cost_delay: 2
>> autovacuum_naptime: 1s
>> max_files_per_process: 4096
>> archive_mode: on
>> archive_timeout: 1800s
>> archive_command: cd .
>> wal_level: replica
>> wal_keep_size: 2GB
>> max_wal_senders: 10
>> max_replication_slots: 10
>> hot_standby: on
>> wal_log_hints: on
>> wal_compression: on
>> shared_preload_libraries: pgaudit
>> track_io_timing: on
>> log_lock_waits: on
>> log_temp_files: 0
>> track_activities: on
>> track_counts: on
>> track_functions: all
>> log_checkpoints: on
>> logging_collector: on
>> log_truncate_on_rotation: on
>> log_rotation_age: 1d
>> log_rotation_size: 1GB
>> log_line_prefix: '%m [%p]: [%l-1] db=%d,user=%u,app=%a,client=%h '
>> log_filename: postgresql-%Y-%m-%d.log
>> log_directory: /var/log/pgsql
>> log_connections: on
>> log_disconnections: on
>> log_statement: ddl
>> log_error_verbosity: verbose
>> hot_standby_feedback: on
>> max_standby_streaming_delay: 30s
>> wal_receiver_status_interval: 10s
>> idle_in_transaction_session_timeout: 10min
>> jit: off
>> max_worker_processes: 24
>> max_parallel_workers: 8
>> max_parallel_workers_per_gather: 2
>> max_parallel_maintenance_workers: 2
>>
>> initdb:
>> - encoding: UTF8
>> - data-checksums
>>
>> pg_hba:
>> - host replication replicator 127.0.0.1/32 md5
>>
>> - host replication replicator x.x.x.98/27 scram-sha-256
>>
>>
>>
>> - host replication replicator x.x.x.99/27 scram-sha-256
>>
>>
>>
>> - host replication replicator x.x.x.100/27 scram-sha-256
>>
>>
>> - host all all 0.0.0.0/0 md5
>>
>> postgresql:
>> listen: x.x.x.98:5432
>> connect_address: x.x.x.98:5432
>> data_dir: /var/lib/pgsql/data
>> bin_dir: /usr/bin
>> pgpass: /var/lib/pgsql/.pgpass_patroni
>> authentication:
>> replication:
>> username: replicator
>> password: password
>> superuser:
>> username: postgres
>> password: password
>> parameters:
>> unix_socket_directories: /var/run/postgresql
>>
>> remove_data_directory_on_rewind_failure: false
>> remove_data_directory_on_diverged_timelines: false
>>
>> create_replica_methods:
>> - basebackup
>> basebackup:
>> max-rate: '100M'
>> checkpoint: 'fast'
>>
>> watchdog:
>> mode: required
>> device: /dev/watchdog
>> safety_margin: 5
>>
>> tags:
>> nofailover: false
>> noloadbalance: false
>> clonefrom: false
>> nosync: false
>>
>> 4) Definition of 'ridiculous rate'.
>>
>> 1GB / day
>>
>> 5) Relevant information from the logs.
>>
>> Below entry is something taken off today's log until this point in time
>> which I think it might be relevant. I cannot see any specifics. If there is
>> anything else please let me know.
>>
>> 2<REDACTED>:<REDACTED> GMT [186889]: [863-1] db=,user=,app=,client= LOG:
>> 00000: checkpoint starting: time
>> 2<REDACTED>:<REDACTED> GMT [186889]: [864-1] db=,user=,app=,client=
>> LOCATION: LogCheckpointStart, xlog.c:6121
>> 2<REDACTED>:<REDACTED> GMT [186889]: [865-1] db=,user=,app=,client= LOG:
>> 00000: checkpoint complete: wrote 66 buffers (0.4%); 0 WAL file(s) added,
>> 0 removed, 0 recycled; write=6.563 s, sync=0.003 s, total=6.619 s; sync
>> files=22, longest=0.002 s, average=0.001 s; distance=776 kB, estimate=56426
>> kB
>> 2<REDACTED>:<REDACTED> GMT [186889]: [866-1] db=,user=,app=,client=
>> LOCATION: LogCheckpointEnd, xlog.c:6202
>> 2<REDACTED>:<REDACTED> GMT [2439188]: [7-1]
>> db=documentation-database,user=documentation-database-user,app=PostgreSQL
>> JDBC Driver,client=<REDACTED> LOG: 00000: disconnection: session time:
>> 0:<REDACTED> user=documentation-database-user
>> database=documentation-database host=<REDACTED> port=56170
>>
>>
>> @Laurenz
>>
>> I guess you are referring to
>> https://www.cybertec-postgresql.com/en/why-does-my-pg_wal-keep-growing/
>>
>> *Yes, that is the one.*
>>
>> I listed all the reasons I know for your predicament.
>> Did you do some research along these lines?
>>
>> *I've had a look at the things that you have mentioned in the guide. *
>>
>> If yes, what did you find?
>>
>> *I've not managed to test the queries out yet. But I am planning to test
>> out in my lab environment.*
>> *Sorry am really cautious about this as those are the main production
>> databases.*
>>
>> *Hope the above is going to give a bit of insight on the root cause of
>> the problem.*
>>
>>
>>
>> Yours,
>> Laurenz Albe
>>
>>
>>
>> On Wed, Jan 22, 2025 at 6:03 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
>> wrote:
>>
>>> On 1/22/25 09:33, Paul Brindusa wrote:
>>> > Good afternoon,
>>> >
>>> > Following below we are facing a similar issue and im getting a real
>>> buzz
>>> > to get this working myself, speaking to my DBA in the company has
>>> > actually left me a bit cold as he is not good with postgres.
>>> >
>>> > So I want to try and get a solution for this and fix this issue with
>>> the
>>> > pg_wal files filling up the drive at a ridiculous rate. I have been
>>> > manually moving logs to a different directory but have had no luck in
>>> > finding an actual solution.
>>> >
>>> > The cluster is a 3 node cluster with HA which is running wirth patroni.
>>> >
>>> > Please help me out, I will mention that I have test cluster spun up in
>>> > case something needs testing.
>>> >
>>> > Also want to give a shout out to Lorenz Albe's for posting stuff about
>>> > wal files on his company blog.
>>> >
>>> > Again any help will be greatly appreciated.
>>>
>>> A good deal more information is needed to troubleshoot this:
>>>
>>> 1) Postgres version(s).
>>>
>>> 2) The Patroni version.
>>>
>>> 3) The Patroni configuration.
>>>
>>> 4) Definition of 'ridiculous rate'.
>>>
>>> 5) Relevant information from the logs.
>>>
>>> >
>>> >
>>> > " On one of our postgres instances we have the pg_wal/data folder up
>>> to
>>> > 196GB, out of 200GB disk filled up.
>>> > This has stopped the posgresql.service this morning causing two
>>> > applications to crash.
>>> > Unfortunately our database admin is on leave today, and we are trying
>>> to
>>> > figure out how to get the disk down?
>>> > Any ideas or suggestions are more than welcome.
>>> >
>>> > Thank you in advance."
>>> >
>>> >
>>> > --
>>> > Kind Regards,
>>> > Paul Brindusa
>>> > paulbrindusa88(at)gmail(dot)com <mailto:paulbrindusa88(at)gmail(dot)com>
>>> >
>>>
>>> --
>>> Adrian Klaver
>>> adrian(dot)klaver(at)aklaver(dot)com
>>>
>>>
>>
>> --
>> Kind Regards,
>> Paul Brindusa
>> paulbrindusa88(at)gmail(dot)com
>>
>>

--
Kind Regards,
Paul Brindusa
paulbrindusa88(at)gmail(dot)com