006.PGSQL-数据倾斜、数据各节点分布情况；创建序列、创建分布式表

数据倾斜、数据各节点分布情况、创建分布式表

查看表的分布节点

-- 查看表是否数据倾斜
select table_skewness('b_st_yz_aj_cgajfj');

-- 在哪个节点分布

-- 查看表是否数据倾斜 
select table_skewness('b_st_yz_aj_cgajfj');
 
 -- 在哪个节点分布
select 
xc_node_id, count(1) 
from tablename 
group by xc_node_id 
order by xc_node_id desc;

创建序列、创建分布式表

创建序列

CREATE SEQUENCE "ioc_theme"."m_ss_qyqy_move_warn_success_rid_seq" 
INCREMENT 1
MINVALUE  1
MAXVALUE 9223372036854775807
START 1
CACHE 1
CYCLE ;

SELECT setval('"ioc_theme"."m_ss_qyqy_move_warn_success_rid_seq"', -1, false);

ALTER SEQUENCE "ioc_theme"."m_ss_qyqy_move_warn_success_rid_seq" OWNER TO "zsj_qh";

删除序列  修改序列

----删除前先解除 id 对该序列的依赖
ALTER TABLE tablename ALTER COLUMN id SET DEFAULT null;
DROP SEQUENCE IF EXISTS sequence_name;

修改自增序列开始值
---- id_max 即 id 目前的最大值，可写为1，可通过 “SELECT MAX(id) FROM tablename” 得到

CREATE SEQUENCE sequence_name START WITH id_max;
修改自增序列所属的表和字段
ALTER TABLE ioc_theme.m_ss_yqjc_sbryxxb_51_af ALTER COLUMN rid SET DEFAULT nextval('ioc_theme.m_ss_yqjc_sbryxxb_51_af_rid_seq'::regclass);

查询表的序列

select table_schema, 
       table_name,
       column_name,
       data_type,
       column_default,
       is_nullable
  from information_schema.columns
 where table_name = 'm_gd_yqjc_sbryxxb_0501_0520';

创建分布式表

CREATE TABLE "ioc_theme"."m_hz_cyrk_rk_education" (
  "rid" int4 NOT NULL DEFAULT nextval('"ioc_theme".m_hz_cyrk_rk_education_rid_seq'::regclass),
  "occur_period" int4,
  "occur_period_year" int4,
  "occur_period_month" int4,
  "area_code_abode" varchar(20) COLLATE "pg_catalog"."default",
  "area_code_work" varchar(20) COLLATE "pg_catalog"."default",
  "degree" varchar(40) COLLATE "pg_catalog"."default",
  "employ_num" int4,
  "employ_ratio" numeric(20,2),
  "create_time" timestamp(6) DEFAULT pg_systimestamp(),
  "update_time" timestamp(6) DEFAULT pg_systimestamp(),
  CONSTRAINT "m_hz_cyrk_rk_education_pkey" PRIMARY KEY ("rid")
)
;

ALTER TABLE "ioc_theme"."m_hz_cyrk_rk_education" 
  OWNER TO "zsj_qh";

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."rid" IS '行ID';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."occur_period" IS '报告期';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."occur_period_year" IS '报告期(年)';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."occur_period_month" IS '报告期(月)';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."area_code_abode" IS '居住地行政区划代码（社区）';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."area_code_work" IS '工作地行政区划代码';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."degree" IS '学历';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."employ_num" IS '人数';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."employ_ratio" IS '占比';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."create_time" IS '数据创建时间';

COMMENT ON COLUMN "ioc_theme"."m_hz_cyrk_rk_education"."update_time" IS '更新时间';

COMMENT ON TABLE "ioc_theme"."m_hz_cyrk_rk_education" IS '人才专题接口';