Re: [Ext:] Re: Stream Replication not working - Mailing list pgsql-hackers
| From | Sushant Postgres |
|---|---|
| Subject | Re: [Ext:] Re: Stream Replication not working |
| Date | |
| Msg-id | CAHzMYRLz+hYo6zK+US8EmQ6CAuAXXvCHNGbwCNpw9A=GATcQ_g@mail.gmail.com Whole thread Raw |
| In response to | Re: [Ext:] Re: Stream Replication not working (Allie Crawford <CrawfordMA@ChurchofJesusChrist.org>) |
| Responses |
Re: [Ext:] Re: Stream Replication not working
|
| List | pgsql-hackers |
Thank you so much for your help on this Satya. I have detailed right below the output of the query you asked me to run.
Master
postgresql@<master> ~>psql
psql (13.5)
Type "help" for help.
postgresql=# select * from pg_locks;
locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath
------------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+---------+-----------------+---------+----------
relation | 16384 | 12141 | | | | | | | | 3/6715 | 2669949 | AccessShareLock | t | t
virtualxid | | | | | 3/6715 | | | | | 3/6715 | 2669949 | ExclusiveLock | t | t
(2 rows)
postgresql=#
Standby
postgresql@<standby> ~>psql
psql (13.5)
Type "help" for help.
postgresql=# select * from pg_locks;
locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath
------------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+--------+-----------------+---------+----------
relation | 16384 | 12141 | | | | | | | | 2/50 | 642064 | AccessShareLock | t | t
virtualxid | | | | | 2/50 | | | | | 2/50 | 642064 | ExclusiveLock | t | t
virtualxid | | | | | 1/1 | | | | | 1/0 | 17333 | ExclusiveLock | t | t
(3 rows)
postgresql=#
From: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Date: Monday, January 10, 2022 at 1:06 PM
To: Allie Crawford <CrawfordMA@ChurchofJesusChrist.org>
Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>
Subject: [Ext:] Re: Stream Replication not working[External Email]
Seems there is a problem with the replay on your standby. Either it is too slow or stuck behind some locks ( replay_lag of 20:38:47.00904 indicates this and the flush_lsn is the same as lsn on primary ) . Run pg_locks to see if the replay is stuck behind a lock.
On Mon, Jan 10, 2022 at 11:53 AM Allie Crawford <CrawfordMA@churchofjesuschrist.org> wrote:
Hi All,
I have implemented Stream replication in one of my environments, and for some reason even though all the health checks are showing that the replication is working, when I run manual tests to see if changes are being replicated, the changes are not replicated to the standby postgresql environment. I have been researching for two day and I cannot find any documentation that talks about the case I am running into. I will appreciate if anybody could take a look at the details I have detailed below and give me some guidance on where the problem might be that is preventing my changes for being replicated. Even though I was able to instantiate the standby while firewalld was enabled, I decided to disable it just in case that it was causing any issue to the manual changes, but disabling firewalld has not had any effect, I am still not able to get the manual changes test to be replicated to the standby site. As you will see in the details below, the streaming is working, both sites are in sync to the latest WAL but for some reasons the latest changes are not on the standby site. How is it possible that the standby site is completely in sync but yet does not contain the latest changes?
Thanks in advance for any help you can give me with this problem.
Regards,
Allie
Details:
Master postgresql Environment
postgresql=# select * from pg_stat_replication;
-[ RECORD 1 ]----+------------------------------
pid | 1979089
usesysid | 16404
usename | replacct
application_name | walreceiver
client_addr | <standby server IP>
client_hostname | <standby server name>
client_port | 55096
backend_start | 2022-01-06 17:29:51.542784-07
backend_xmin |
state | streaming
sent_lsn | 0/35000788
write_lsn | 0/35000788
flush_lsn | 0/35000788
replay_lsn | 0/31000500
write_lag | 00:00:00.001611
flush_lag | 00:00:00.001693
replay_lag | 20:38:47.00904
sync_priority | 1
sync_state | sync
reply_time | 2022-01-07 14:11:58.996277-07
postgresql=#
postgresql=# select * from pg_roles;
rolname | rolsuper | rolinherit | rolcreaterole | rolcreatedb | rolcanlogin | rolreplication | rolconnlimit | rolpassword | rolvaliduntil | rolbypassrls | rolconfig | oid
---------------------------+----------+------------+---------------+-------------+-------------+----------------+--------------+-------------+---------------+--------------+-----------+-------
postgresql | t | t | t | t | t | t | -1 | ******** | | t | | 10
pg_monitor | f | t | f | f | f | f | -1 | ******** | | f | | 3373
pg_read_all_settings | f | t | f | f | f | f | -1 | ******** | | f | | 3374
pg_read_all_stats | f | t | f | f | f | f | -1 | ******** | | f | | 3375
pg_stat_scan_tables | f | t | f | f | f | f | -1 | ******** | | f | | 3377
pg_read_server_files | f | t | f | f | f | f | -1 | ******** | | f | | 4569
pg_write_server_files | f | t | f | f | f | f | -1 | ******** | | f | | 4570
pg_execute_server_program | f | t | f | f | f | f | -1 | ******** | | f | | 4571
pg_signal_backend | f | t | f | f | f | f | -1 | ******** | | f | | 4200
replacct | t | t | t | t | t | t | -1 | ******** | | t | | 16404
(10 rows)
postgresql=#
postgresql=# create database test_replication_3;
CREATE DATABASE
postgresql=#
postgresql=# select datname from pg_database;
datname
--------------------
postgres
postgresql
template1
template0
stream
test_replication
test_replication_2
test_replication_3
(8 rows)
postgresql=#
postgresql=# SELECT pg_current_wal_lsn();
pg_current_wal_lsn
--------------------
0/35000788
(1 row)
postgresql=#
Standby postgresql Environment
postgresql=# select * from pg_stat_wal_receiver;
-[ RECORD 1 ]---------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
pid | 17340
status | streaming
receive_start_lsn | 0/30000000
receive_start_tli | 1
written_lsn | 0/35000788
flushed_lsn | 0/35000788
received_tli | 1
last_msg_send_time | 2022-01-07 14:09:48.766823-07
last_msg_receipt_time | 2022-01-07 14:09:48.767581-07
latest_end_lsn | 0/35000788
latest_end_time | 2022-01-07 14:08:48.663693-07
slot_name | wal_req_x_replica
sender_host | <Master Server IP>
sender_port | <Master server postgresql port#>
conninfo | user=replacct password=******** channel_binding=prefer dbname=replication host=<Master server IP> port=<postgresql port#> fallback_application_name=walreceiver sslmode=prefer sslcompression=0 ssl_min_protocol_version=TLSv1.2 gssencmode=prefer krbsrvname=postgres target_session_attrs=any
postgresql=#
postgresql=# select datname from pg_database;
datname
------------
postgres
postgresql
template1
template0
stream
(5 rows)
postgresql=# select pg_last_wal_receive_lsn();
pg_last_wal_receive_lsn
-------------------------
0/35000788
(1 row)
postgresql=#
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