added initial setup of replicas

files/postgres/primary/init.sh

@@ -1,3 +1,10 @@
 #!/bin/bash
 
-echo "include '/files/postgres/primary/primary_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+echo "include '/files/postgres/primary/primary_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+
+psql -U mmuser -d mattermost -c "create role replicauser with replication password 'replicauser_password' login"
+psql -U mmuser -d mattermost -c "select pg_create_physical_replication_slot('replica_2_slot');"
+psql -U mmuser -d mattermost -c "select pg_create_physical_replication_slot('replica_1_slot');"
+
+
+echo "host    replication     replicauser    0.0.0.0/0   md5" >> /var/lib/postgresql/data/pg_hba.conf

files/postgres/primary/primary_config.conf

@@ -1,9 +1,14 @@
-# This value should match the "SqlSettings.MaxConnections" value within your config.json for Mattermost
-# This is a suggestion and can be set lower / higher based on the size of your server.
-max_connections = 1020
-tcp_keepalives_idle = 5
-tcp_keepalives_interval = 1
-tcp_keepalives_count = 5
+# If the instance is lower capacity than r5.xlarge, then set it to a lower number.
+# Also tune the "MaxOpenConns" setting under the "SqlSettings" of the Mattermost app accordingly.
+# Note that "MaxOpenConns" on Mattermost is per data source name.
+max_connections = 1024
+
+# Set it to 1.1, unless the DB is using spinning disks.
+random_page_cost = 1.1
+
+# This should be 32MB if using read replicas, or 16MB if using a single PostgreSQL instance.
+# If the instance is of a lower capacity than r5.xlarge, then set it to a lower number.
+work_mem = 16MB
 
 # Set both of the below settings to 65% of total memory. For a 32 GB instance, it should be 21 GB.
 # If on a smaller server, set this to 20% or less total RAM.
@@ -11,15 +16,27 @@ tcp_keepalives_count = 5
 shared_buffers = 512MB
 effective_cache_size = 512MB
 
-# Set it to 16 MB for readers and 32 MB for writers. If it's a single instance, 16 MB should be sufficient. If the instance is of a lower capacity than r5.xlarge, then set it to a lower number.
-work_mem = 16MB
+# If you are using pgbouncer, or any similar connection pooling proxy,
+# in front of your DB, then apply the keepalive settings to the proxy instead,
+# and revert the keepalive settings for the DB back to defaults.
+tcp_keepalives_idle = 5
+tcp_keepalives_interval = 1
+tcp_keepalives_count = 5
 
 # 1GB (reduce this to 512MB if your server has less than 32GB of RAM)
-autovacuum_work_mem = 512MB
+maintenance_work_mem = 512MB
+
 autovacuum_max_workers = 4
 autovacuum_vacuum_cost_limit = 500
 
-#Set it to 1.1 unless the DB is using spinning disks.
-random_page_cost = 1.1
+## Intentionally disabled here because running in docker this may cause performance problems.
 
-restart_after_crash = on
+# If you have more than 32 CPUs on your database server, please set the following options to utilize more CPU for your server:
+# max_worker_processes = 12
+# max_parallel_workers_per_gather = 4
+# max_parallel_workers = 12
+# max_parallel_maintenance_workers = 4
+
+log_connections = on
+log_disconnections = on
+log_replication_commands = on

files/postgres/replica/init.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+set -e
+
+echo "include '/files/postgres/replica/replica_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+cp /var/lib/postgresql/data/postgresql.conf /files/postgres/replica/baseconfig.conf
+
+
+rm -rf /var/lib/postgresql/data/*
+export PGPASSWORD='replicauser_password'
+pg_basebackup -h cs-repro-postgres -p 5432 -U replicauser -D /var/lib/postgresql/data -Fp -Xs -R
+
+rm -rf /var/lib/postgresql/data/postgresql.conf
+
+cp /files/postgres/replica/baseconfig.conf /var/lib/postgresql/data/postgresql.conf
+
+exec pg_ctl -D /var/lib/postgresql/data start

files/postgres/replica/replica_1/init.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -e
+
+echo "include '/files/postgres/replica/replica_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+echo "include '/files/postgres/replica/replica_1/replica_1_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+
+cp /var/lib/postgresql/data/postgresql.conf /files/postgres/replica/replica_1/baseconfig.conf
+
+
+rm -rf /var/lib/postgresql/data/*
+export PGPASSWORD='replicauser_password'
+pg_basebackup -h cs-repro-postgres -p 5432 -U replicauser -D /var/lib/postgresql/data -Fp -Xs -R
+
+rm -rf /var/lib/postgresql/data/postgresql.conf
+
+cp /files/postgres/replica/replica_1/baseconfig.conf /var/lib/postgresql/data/postgresql.conf
+
+exec pg_ctl -D /var/lib/postgresql/data start

files/postgres/replica/replica_1/replica_1_config.conf

@@ -0,0 +1,3 @@
+# replication slot on sending server
+# This needs to be configured using the docs below for "Keeping the replica and primary in sync."
+primary_slot_name = 'replica_1_slot'

files/postgres/replica/replica_2/init.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -e
+
+echo "include '/files/postgres/replica/replica_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+echo "include '/files/postgres/replica/replica_2/replica_2_config.conf'" >> /var/lib/postgresql/data/postgresql.conf
+
+cp /var/lib/postgresql/data/postgresql.conf /files/postgres/replica/replica_2/baseconfig.conf
+
+
+rm -rf /var/lib/postgresql/data/*
+export PGPASSWORD='replicauser_password'
+pg_basebackup -h cs-repro-postgres -p 5432 -U replicauser -D /var/lib/postgresql/data -Fp -Xs -R
+
+rm -rf /var/lib/postgresql/data/postgresql.conf
+
+cp /files/postgres/replica/replica_2/baseconfig.conf /var/lib/postgresql/data/postgresql.conf
+
+exec pg_ctl -D /var/lib/postgresql/data start

files/postgres/replica/replica_2/replica_2_config.conf

@@ -0,0 +1,3 @@
+# replication slot on sending server
+# This needs to be configured using the docs below for "Keeping the replica and primary in sync."
+primary_slot_name = 'replica_2_slot'

files/postgres/replica/replica_config.conf

@@ -0,0 +1,64 @@
+# If the instance is lower capacity than r5.xlarge, then set it to a lower number.
+# Also tune the "MaxOpenConns" setting under the "SqlSettings" of the Mattermost app accordingly.
+# Note that "MaxOpenConns" on Mattermost is per data source name.
+max_connections = 1024
+
+# Set it to 1.1, unless the DB is using spinning disks.
+random_page_cost = 1.1
+
+# This should be 32MB if using read replicas, or 16MB if using a single PostgreSQL instance.
+# If the instance is of a lower capacity than r5.xlarge, then set it to a lower number.
+work_mem = 16MB
+
+# Set both of the below settings to 65% of total memory. For a 32 GB instance, it should be 21 GB.
+# If on a smaller server, set this to 20% or less total RAM.
+# ex: 512MB would work for a 4GB RAM server
+shared_buffers = 512MB
+effective_cache_size = 512MB
+
+# If you are using pgbouncer, or any similar connection pooling proxy,
+# in front of your DB, then apply the keepalive settings to the proxy instead,
+# and revert the keepalive settings for the DB back to defaults.
+tcp_keepalives_idle = 5
+tcp_keepalives_interval = 1
+tcp_keepalives_count = 5
+
+# 1GB (reduce this to 512MB if your server has less than 32GB of RAM)
+maintenance_work_mem = 512MB
+
+autovacuum_max_workers = 4
+autovacuum_vacuum_cost_limit = 500
+
+## Intentionally disabled here because running in docker this may cause performance problems.
+
+# If you have more than 32 CPUs on your database server, please set the following options to utilize more CPU for your server:
+# max_worker_processes = 12
+# max_parallel_workers_per_gather = 4
+# max_parallel_workers = 12
+# max_parallel_maintenance_workers = 4
+
+
+# If the instance is lower capacity than r5.xlarge, then set it to a lower number.
+# Also tune the "MaxOpenConns" setting under the "SqlSettings" of the Mattermost app accordingly.
+# Note that "MaxOpenConns" on Mattermost is per data source name.
+max_connections = 1024
+
+# This setting should be 16MB on read nodes, and 32MB on writer nodes
+work_mem = 16MB
+
+# The below settings allow the reader to return query results even when the primary has a write process running, a query conflict.
+# This is set to on because of the high volume of write traffic that can prevent the reader from returning query results within the timeout.
+# https://www.postgresql.org/docs/current/hot-standby.html#HOT-STANDBY-CONFLICT
+hot_standby = on
+hot_standby_feedback = on
+
+# connection string to sending server
+# This was created when you added a replication role to the primary database.
+# username - replace "test" with the role you made
+# password - replace "testpassword" with the role password
+# host - replace "x.x.x.x" with your IP or URL string.
+primary_conninfo = 'host=cs-repro-postgres port=5432 user=replicauser password=replicauser_password'
+
+log_connections = on
+log_disconnections = on
+log_replication_commands = on