* moved frmo https://og2k.com/pub/configure/software/db/postgresql/ to https://github.com/InstallAndUse/RPi some PostgreSQL replication related installation notes /A

setup_replication_of_historical_data_from_sensors_to_server_using_PostgreSQL/PostgreSQL (publisher) @RPi (Debian).md

@@ -0,0 +1,87 @@
+# 2020 06 12  + init /A
+# 2022 03 19  + published on https://github.com/InstallAndUse/RPi /A
+
+# set publication (logical replication)
+# first we need to create user who will be subscribed to this publication
+# (again, to keep it simple, (user2) is a name of (host2) which will login)
+CREATE USER (user2) WITH PASSWORD '(pass2)';
+\du
+CREATE PUBLICATION telemetry_host FOR TABLE telemetry_host;
+SELECT * FROM pg_catalog.pg_publication;
+\d telemetry_host
+
+# grant readonly access on subscription to (user2)
+ALTER ROLE (user2) REPLICATION ;
+GRANT SELECT ON telemetry_host TO (user2);
+\c telemetry
+GRANT ALL ON TABLE public.telemetry_lab5rp41 TO lab5rp41 ;
+
+# exit to console and insert into DB first entry
+exit
+psql -h localhost -U lab5rp41 -d telemetry -c "INSERT INTO telemetry_lab5rp41 (timestamp, sensor, value) VALUES (now(), 'test_sensor', '12345')"
+    Password for user (user):
+    INSERT 0 1
+
+# check select with (user2)
+psql -h localhost -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
+    Password for user (user2):
+               timestamp           | value |                              sensor
+    -------------------------------+-------+------------------------------------------------------------------
+     2020-06-12 08:58:36.732033+01 | 12345 | test_sensor
+    (1 row)
+
+# open access to database from network
+# trying access DB to IP address (not to localhost), should denied access
+ip a
+psql -h (host_ip) -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
+    psql: could not connect to server: Connection refused
+      Is the server running on host "192.168.xxx.xxx" and accepting
+      TCP/IP connections on port 5432?
+# become root (logout postgres)
+exit
+sudo
+
+# on moment of writing, configs for postgres on RPi are here, may differ for different linux distros
+# enable listening on all interfaces
+nano /etc/postgresql/11/main/postgresql.conf
+    # - Connection Settings -
+    listen_addresses = '*'
+    wal_level = logical
+
+# enable auth method
+nano /etc/postgresql/11/main/pg_hba.conf
+# we need to open network access for IPv4 and IPv6 (as RPi obtain IPv6 from DHCP as well)
+# in this case, I am opening only access to DB telemetry and only for user (user2)
+    # IPv4 local connections:
+    host    all             all            127.0.0.1/32            md5
+    host    replication     (user2)        0.0.0.0/0               md5
+    host    telemetry       (user2)        0.0.0.0/0               md5
+    # IPv6 local connections:
+    host    all             all            ::1/128                 md5
+    host    replication     (user2)        ::0/0                   md5
+    host    telemetry       (user2)        ::0/0                   md5
+
+# save, and restart postresql cluster
+systemctl | grep sql
+systemctl restart postgresql@11-main.service
+
+# check that postgres is listening on network interfaces
+netstat -ntap | grep 5432
+    # postgres listens only on localhost
+    tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN      1796/postgres
+    tcp6       0      0 ::1:5432                :::*                    LISTEN      1796/postgres
+
+# now try again
+psql -h (host_ip) -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
+    Password for user lab5dle4:
+               timestamp           | value |                              sensor
+    -------------------------------+-------+------------------------------------------------------------------
+     2020-06-12 08:58:36.732033+01 | 12345 | test_sensor
+    (1 row)
+# it is important to set it up correctly to this point to avoid confusion later on setting up subsciber-side
+
+# open firewall, if needed for tcp/5432 (by default it is opened)
+iptables -L -n -v --line-numbers | grep 5432
+
+
+# reboot and retry last SELECT command, everything should work

setup_replication_of_historical_data_from_sensors_to_server_using_PostgreSQL/PostgreSQL (subscriber) @Fedora31.md

@@ -0,0 +1,60 @@
+2020 05 26
+
+https://www.scalingpostgres.com/tutorials/
+https://www.percona.com/blog/2018/09/07/setting-up-streaming-replication-postgresql/
+https://www.howtoforge.com/tutorial/postgresql-replication-on-ubuntu-15-04/
+https://blog.raveland.org/post/postgresql_lr_en/
+https://blog.dbi-services.com/in-core-logical-replication-will-hit-postgresql-10/
+https://debezium.io/documentation/reference/postgres-plugins.html
+https://paquier.xyz/postgresql-2/postgres-9-4-feature-highlight-basics-logical-decoding/
+
+
+# install server
+yum install postgresql-server
+/usr/bin/postgresql-setup --initdb
+
+
+# make sure local cluster exist
+su - postgres
+pg_ctl -D /var/lib/pgsql/data/10-main initdb
+pg_ctl -D /var/lib/pgsql/data/10-main -l logfile start
+
+
+# create a cluster for replica
+su - postgres
+pg_ctl -D /var/lib/pgsql/data/20-replica-lab5rpz1 initdb
+
+# run and test
+pg_ctl -D /var/lib/pgsql/data/20-replica-lab5rpz1 start -l logfile
+psql -p 5433 postgres
+C-C
+
+# ensure, that correct DB is started as service
+systemctl enable postgresql
+nano /usr/lib/systemd/system/postgresql.service
+    Environment=PGDATA=/var/lib/pgsql/data/10-main
+systemctl daemon-reload
+systemctl start postgresql
+
+# check replication status
+psql
+# expect logical
+SHOW wal_level;
+
+# create identical table as on publisher
+CREATE TABLE ...
+
+# create subscription for first satellite
+# with IP
+CREATE SUBSCRIPTION lab5rpz1_main CONNECTION 'host=192.168.7.134 port=5432 user=(user2) password=123 dbname=postgres' PUBLICATION main;
+# then I realized, it is possible to use hostname, which will be resolved over network, in case IP address will change. Genius. :)
+ALTER  SUBSCRIPTION lab5rpz1_main CONNECTION 'host=lab5rpz1      port=5432 user=(user2) password=123 dbname=postgres';
+
+# second satellite
+CREATE TABLE telemetry_lab5rp41;
+CREATE SUBSCRIPTION telemetry_lab5rp41 CONNECTION 'host=lab5rp41 port=5432 user=(user2) password=(user2)123 dbname=telemetry' PUBLICATION telemetry_lab5rp41;
+GRANT ALL ON TABLE telemetry_lab5rp41 TO (user2) ;
+
+
+# check replication
+SELECT * FROM pg_stat_replication;

setup_replication_of_historical_data_from_sensors_to_server_using_PostgreSQL/README.md

@@ -1,90 +1,5 @@
-# In this project we shall setup replication between PostgreSQL DataBases (DBs) to move historical data of DS18x20 sensors from measurement units to server.
-
-# 2020 06 12  + init /A
 # 2022 03 19  + published on https://github.com/InstallAndUse/RPi /A
 
+In this project we shall setup replication between PostgreSQL DataBases (DBs) to move historical data of DS18x20 sensors from measurement units to server.
 
-# set publication (logical replication)
-# first we need to create user who will be subscribed to this publication
-# (again, to keep it simple, (user2) is a name of (host2) which will login)
-CREATE USER (user2) WITH PASSWORD '(pass2)';
-\du
-CREATE PUBLICATION telemetry_host FOR TABLE telemetry_host;
-SELECT * FROM pg_catalog.pg_publication;
-\d telemetry_host
-
-# grant readonly access on subscription to (user2)
-ALTER ROLE (user2) REPLICATION ;
-GRANT SELECT ON telemetry_host TO (user2);
-\c telemetry
-GRANT ALL ON TABLE public.telemetry_lab5rp41 TO lab5rp41 ;
-
-# exit to console and insert into DB first entry
-exit
-psql -h localhost -U lab5rp41 -d telemetry -c "INSERT INTO telemetry_lab5rp41 (timestamp, sensor, value) VALUES (now(), 'test_sensor', '12345')"
-    Password for user (user):
-    INSERT 0 1
-
-# check select with (user2)
-psql -h localhost -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
-    Password for user (user2):
-               timestamp           | value |                              sensor
-    -------------------------------+-------+------------------------------------------------------------------
-     2020-06-12 08:58:36.732033+01 | 12345 | test_sensor
-    (1 row)
-
-# open access to database from network
-# trying access DB to IP address (not to localhost), should denied access
-ip a
-psql -h (host_ip) -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
-    psql: could not connect to server: Connection refused
-      Is the server running on host "192.168.xxx.xxx" and accepting
-      TCP/IP connections on port 5432?
-# become root (logout postgres)
-exit
-sudo
-
-# on moment of writing, configs for postgres on RPi are here, may differ for different linux distros
-# enable listening on all interfaces
-nano /etc/postgresql/11/main/postgresql.conf
-    # - Connection Settings -
-    listen_addresses = '*'
-    wal_level = logical
-
-# enable auth method
-nano /etc/postgresql/11/main/pg_hba.conf
-# we need to open network access for IPv4 and IPv6 (as RPi obtain IPv6 from DHCP as well)
-# in this case, I am opening only access to DB telemetry and only for user (user2)
-    # IPv4 local connections:
-    host    all             all            127.0.0.1/32            md5
-    host    replication     (user2)        0.0.0.0/0               md5
-    host    telemetry       (user2)        0.0.0.0/0               md5
-    # IPv6 local connections:
-    host    all             all            ::1/128                 md5
-    host    replication     (user2)        ::0/0                   md5
-    host    telemetry       (user2)        ::0/0                   md5
-
-# save, and restart postresql cluster
-systemctl | grep sql
-systemctl restart postgresql@11-main.service
-
-# check that postgres is listening on network interfaces
-netstat -ntap | grep 5432
-    # postgres listens only on localhost
-    tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN      1796/postgres
-    tcp6       0      0 ::1:5432                :::*                    LISTEN      1796/postgres
-
-# now try again
-psql -h (host_ip) -U (user2) -d telemetry -c "SELECT * FROM telemetry_host"
-    Password for user lab5dle4:
-               timestamp           | value |                              sensor
-    -------------------------------+-------+------------------------------------------------------------------
-     2020-06-12 08:58:36.732033+01 | 12345 | test_sensor
-    (1 row)
-# it is important to set it up correctly to this point to avoid confusion later on setting up subsciber-side
-
-# open firewall, if needed for tcp/5432 (by default it is opened)
-iptables -L -n -v --line-numbers | grep 5432
-
-
-# reboot and retry last SELECT command, everything should work
+there are many variants to deploy such replication. In my case Dell Latitude laptop with Fedora 31 was used to act as satellite to acquire telemetry from sensors. I shall keep this project open, because there are many other interesting setups to appear, using different operating systems.