primary_write.rb

require 'pg'

uri = ''


file = File.open('tmp/write.txt', 'w')

while true do 
  begin
    conn = PG.connect( uri )
    conn.exec( "INSERT INTO account_deletion_tokens VALUES (1, null, null, null, null, null, NOW(), NOW());" ) do |result|
      file.write("#{Time.now.to_i} - write success\n")
    end
  rescue Exception => e
    file.write("#{Time.now.to_i} - write fail\n")
  end
  sleep(1)
end

read.rb

require 'pg'

uri = ''


file = File.open('tmp/read.txt', 'w')

while true do 
  begin
    conn = PG.connect( uri )
    conn.exec( "SELECT * FROM pg_stat_activity limit 1" ) do |result|
      file.write("#{Time.now.to_i} - read success\n")
    end
  rescue Exception => e
    puts e
    file.write("#{Time.now.to_i} - read fail \n")
  end
  sleep(1)
end

sync_recent.sql

create EXTENSION postgres_fdw;

DROP SCHEMA fgapi;
CREATE SCHEMA fgapi;

DROP SERVER temp_fg;
CREATE SERVER temp_fg
FOREIGN DATA WRAPPER postgres_fdw  
OPTIONS (host HOST, dbname 'fg', port '5432');

DROP USER MAPPING for root server temp_fg;
CREATE USER MAPPING FOR root  
SERVER temp_fg  
OPTIONS (user 'fgapi', password 'PASSWORD');

DROP FOREIGN TABLE fgapi.temp_uploads;
CREATE FOREIGN TABLE fgapi.temp_uploads (  
"id" int8,
"asset_id" varchar(255),
"content_type" varchar(255),
"object_key" text,
"created_at" timestamptz,
"updated_at" timestamptz,
"user_id" int8,
"ip" varchar
)
SERVER temp_fg  
OPTIONS (schema_name 'public', table_name 'uploads');

INSERT INTO public.uploads (asset_id, content_type, object_key, created_at, updated_at, user_id, ip)
SELECT asset_id, content_type, object_key, created_at, updated_at, user_id, ip
FROM fgapi.temp_uploads old 
where not exists (select * from public.uploads where asset_id = old.asset_id)
order by id DESC
limit 1000;


DROP FOREIGN TABLE fgapi.temp_media_variants;
CREATE FOREIGN TABLE fgapi.temp_media_variants (  
"id" int8,
"asset_id" varchar(255),
"asset_type" varchar(255),
"suffix" varchar(255),
"created_at" timestamptz,
"updated_at" timestamptz,
"path" varchar(255),
"file_extension" varchar(255),
"metadata" json
)
SERVER temp_fg  
OPTIONS (schema_name 'public', table_name 'media_variants');


INSERT INTO public.media_variants (asset_id, asset_type, suffix, created_at, updated_at, path, file_extension, metadata)
SELECT asset_id, asset_type, suffix, created_at, updated_at, path, file_extension, metadata
FROM fgapi.temp_media_variants old 
where not exists (select * from public.media_variants where asset_id = old.asset_id)
order by id DESC
limit 1000;

write.rb

require 'pg'

uri = ''


file = File.open('tmp/write.txt', 'w')

while true do 
  begin
    conn = PG.connect( uri )
    conn.exec( "INSERT INTO account_deletion_tokens VALUES (0, null, null, null, null, null, NOW(), NOW());" ) do |result|
      file.write("#{Time.now.to_i} - write success\n")
    end
  rescue Exception => e
    file.write("#{Time.now.to_i} - write fail\n")
  end
  sleep(1)
end