postgresql 分區表

-- 分區表

-- 創建主表
CREATE TABLE measurement (
  city_id   int  not null,
  logdate   date not null,
  peaktemp  int,
  unitsales int
)

  PARTITION BY RANGE (logdate);

-- 創建子表
CREATE TABLE measurement_2019_07
  PARTITION OF measurement
  FOR VALUES FROM ('2019-07-01') TO ('2019-07-31');

-- insert data
insert into measurement
values (1, '2019-07-01', 1, 2);

-- error 沒有對應的子表
insert into measurement
values (1, '2019-08-01', 1, 2);

CREATE TABLE measurement_2019_08
  PARTITION OF measurement
  FOR VALUES FROM ('2019-08-01') TO ('2019-08-30');

-- ok 找到了對應的子表
insert into measurement
values (1, '2019-08-01', 1, 2);

-- detach 子表
ALTER TABLE measurement
  DETACH PARTITION measurement_2019_08;

select *
from measurement; -- 只能看到一條內容

-- attach 子表
ALTER TABLE measurement
  attach PARTITION measurement_2019_08 for VALUES FROM ('2019-08-01') TO ('2019-08-30');

select *
from measurement; -- 可以看到兩條內容了

-- detach
ALTER TABLE measurement
  DETACH PARTITION measurement_2019_08;
select *
from measurement;
-- 更新表字段
alter table measurement
  add test char(200) default '';

select *
from measurement;
select *
from measurement_2019_07; -- attach 的表是 alert 成功的
select *
from measurement_2019_08; -- detach 的表示沒有被 alert 的

-- 將沒有被 alert 的表 attach , 結果炸掉了 提示: child tables is missing column "test"
ALTER TABLE measurement
  attach PARTITION measurement_2019_08 for VALUES FROM ('2019-08-01') TO ('2019-08-30');