Postgresql 远程同步(非实时同步，小数据量)

源端要开通目标的相关访问权限

目标端：

1.建立远程表的视图

create view v_bill_tbl_version_update_control_info as SELECT * FROM dblink('hostaddr=10.10.10.8 port=4321 dbname=postgres user=postgres password=postgres', 'SELECT id,appid,ratio,status,create_time,char_package_name,version from  tbl_version_update_control_info') AS t(id integer,appid  character(20),ratio integer,status character(1),create_time timestamp without time zone,char_package_name character varying(50),version character varying(8)); 

2.建立和远程表一样的判断表以及实体表

CREATE TABLE tbl_version_update_control_info (

    id integer NOT NULL,

    appid character(20) NOT NULL,

    ratio integer DEFAULT 0 NOT NULL,

    status character(1) DEFAULT 0 NOT NULL,

    create_time timestamp without time zone DEFAULT now(),

    char_package_name character varying(50),

    version character varying(8)

);

CREATE TABLE work_table_tbl_version_update_control_info (

    id integer NOT NULL,

    appid character(20) NOT NULL,

    ratio integer DEFAULT 0 NOT NULL,

    status character(1) DEFAULT 0 NOT NULL,

    create_time timestamp without time zone DEFAULT now(),

    char_package_name character varying(50),

    version character varying(8)

);

3.建立同步函数

CREATE OR REPLACE FUNCTION sync_tbl_version_update_control_info()

 RETURNS integer

 LANGUAGE plpgsql

AS $function$

declare

v_src_count int;   --存放源数据统计数据

v_dst_count int;  --存放目标端数据统计数据

v_equal_count int;  --源端和目标端相同的数据

v_run int8;      --统计运行改函数的进行数，如果大于1，说明存在，改函数在运行

begin

v_src_count := 0;

v_dst_count := 0;

v_equal_count := 0;

select count(*) into v_run from pg_stat_activity where query ~ 'sync_tbl_version_update_control_info';

if v_run>1 then

  raise notice 'another process is running, this will exit soon.';

  return 1;

end if;

if (pg_is_in_recovery()) then

  raise notice 'pg_is_in_recovery is true.';

  return 1;

end if;

truncate table ONLY work_table_tbl_version_update_control_info;

insert into work_table_tbl_version_update_control_info 

  (id,appid,ratio,status,create_time,char_package_name,version) 

  select id,appid,ratio,status,create_time,char_package_name,version from v_bill_tbl_version_update_control_info;

select count(*) into v_src_count from work_table_tbl_version_update_control_info;

select count(*) into v_dst_count from tbl_version_update_control_info;

raise notice 'v_src_count:%, v_dst_count:%',v_src_count,v_dst_count;

if ( v_src_count = v_dst_count and v_src_count <> 0 ) then

  select count(*) into v_equal_count from work_table_tbl_version_update_control_info t1,tbl_version_update_control_info t2

    where t1.id=t2.id 

    and t1.appid = t2.appid

    and t1.ratio = t2.ratio

    and t1.status = t2.status

    and t1.create_time = t2.create_time

    and t1.char_package_name = t2.char_package_name

    and t1.version = t2.version;

  raise notice 'v_src_count:%, v_dst_count:%, v_equal_count:%',v_src_count,v_dst_count,v_equal_coun

t;

  if ( v_equal_count <> v_src_count ) then

    truncate table ONLY tbl_version_update_control_info;

    insert into tbl_version_update_control_info 

    (id,appid,ratio,status,create_time,char_package_name,version)

    select id,appid,ratio,status,create_time,char_package_name,version from work_table_tbl_version_update_control_info;

  end if;

elsif ( v_src_count <> v_dst_count and v_src_count <> 0 ) then

  truncate table ONLY tbl_version_update_control_info;

  insert into tbl_version_update_control_info 

  (id,appid,ratio,status,create_time,char_package_name,version)

  select id,appid,ratio,status,create_time,char_package_name,version from work_table_tbl_version_update_control_info;

elsif v_src_count = 0 then

  raise notice 'ERROR: src no data.';

  return 1;

end if;

  return 0;

end;

$function$

4.执行函数进行同步并确认同步

select  sync_tbl_version_update_control_info();

select count(*) from tbl_version_update_control_info;

5.系统定时任务添加：

15 2 * * * /home/postgres/sync_data.sh >>/tmp/sync.log 2>&1

cat /home/postgres/sync_data.sh

echo -e "start sync tbl_version_update_control_info;"

date +%F\ %T

psql -h 127.0.0.1 hank hank -c "select * from sync_tbl_version_update_control_info()";

date +%F\ %T

echo -e "end sync tbl_version_update_control_info;"