大数据Hologres（二）：Hologres 快速入门

文章目录

Hologres 快速入门

一、资源领取

二、入门体验

1、创建数据库

2、创建表

3、导入示例数据

4、查询表中数据

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Hologres 快速入门

一、资源领取

领取链接： 阿里云免费试用 - 阿里云 (aliyun.com)

二、入门体验

1、创建数据库

• 进入Hologres管理控制台，单击左侧实例列表。
• 在实例列表页面，单击实例名称

• 在页面右上角点击登录实例，并新建数据库。

2、创建表

2.1、创建外部表

• 选择SQL编辑器

• 在新增的临时Query查询页面，选择已创建的实例名和数据库 

• 选择已创建的实例名和数据库后，在SQL查询的编辑框输入如下语句，单击运行。

DROP FOREIGN TABLE IF EXISTS odps_customer_10g;
DROP FOREIGN TABLE IF EXISTS odps_lineitem_10g;
DROP FOREIGN TABLE IF EXISTS odps_nation_10g;
DROP FOREIGN TABLE IF EXISTS odps_orders_10g;
DROP FOREIGN TABLE IF EXISTS odps_part_10g;
DROP FOREIGN TABLE IF EXISTS odps_partsupp_10g;
DROP FOREIGN TABLE IF EXISTS odps_region_10g;
DROP FOREIGN TABLE IF EXISTS odps_supplier_10g;

IMPORT FOREIGN SCHEMA "MAXCOMPUTE_PUBLIC_DATA#default" LIMIT to 
(odps_customer_10g,odps_lineitem_10g,odps_nation_10g,odps_orders_10g,odps_part_10g,odps_partsupp_10g,odps_region_10g,odps_supplier_10g
) FROM SERVER odps_server INTO public OPTIONS(if_table_exist'error',if_unsupported_type'error');

 

2.2、创建内部表

以下SQL语句用来创建名称分别为LINEITEM、ORDERS、PARTSUPP、PART、CUSTOMER、SUPPLIER、NATION和REGION的表，用于后续存储数据。

DROP TABLE IF EXISTS LINEITEM;BEGIN;
CREATE TABLE LINEITEM (L_ORDERKEY bigint NOT NULL,L_PARTKEY int NOT NULL,L_SUPPKEY int NOT NULL,L_LINENUMBER int NOT NULL,L_QUANTITY DECIMAL(15, 2) NOT NULL,L_EXTENDEDPRICE DECIMAL(15, 2) NOT NULL,L_DISCOUNT DECIMAL(15, 2) NOT NULL,L_TAX DECIMAL(15, 2) NOT NULL,L_RETURNFLAG text NOT NULL,L_LINESTATUS text NOT NULL,L_SHIPDATE date NOT NULL,L_COMMITDATE date NOT NULL,L_RECEIPTDATE date NOT NULL,L_SHIPINSTRUCT text NOT NULL,L_SHIPMODE text NOT NULL,L_COMMENT text NOT NULL,PRIMARY KEY (L_ORDERKEY, L_LINENUMBER)
);

DROP TABLE IF EXISTS LINEITEM;BEGIN;
CREATE TABLE LINEITEM (L_ORDERKEY bigint NOT NULL,L_PARTKEY int NOT NULL,L_SUPPKEY int NOT NULL,L_LINENUMBER int NOT NULL,L_QUANTITY DECIMAL(15, 2) NOT NULL,L_EXTENDEDPRICE DECIMAL(15, 2) NOT NULL,L_DISCOUNT DECIMAL(15, 2) NOT NULL,L_TAX DECIMAL(15, 2) NOT NULL,L_RETURNFLAG text NOT NULL,L_LINESTATUS text NOT NULL,L_SHIPDATE date NOT NULL,L_COMMITDATE date NOT NULL,L_RECEIPTDATE date NOT NULL,L_SHIPINSTRUCT text NOT NULL,L_SHIPMODE text NOT NULL,L_COMMENT text NOT NULL,PRIMARY KEY (L_ORDERKEY, L_LINENUMBER)
);

CALL set_table_property ('LINEITEM', 'clustering_key', 'L_SHIPDATE,L_ORDERKEY');
CALL set_table_property ('LINEITEM', 'segment_key', 'L_SHIPDATE');
CALL set_table_property ('LINEITEM', 'distribution_key', 'L_ORDERKEY');
CALL set_table_property ('LINEITEM', 'bitmap_columns', 'L_RETURNFLAG,L_LINESTATUS,L_SHIPINSTRUCT,L_SHIPMODE');
CALL set_table_property ('LINEITEM', 'dictionary_encoding_columns', 'l_comment:off,l_returnflag,l_linestatus,l_shipinstruct,l_shipmode');
COMMIT;DROP TABLE IF EXISTS ORDERS;BEGIN;
CREATE TABLE ORDERS (O_ORDERKEY bigint NOT NULL PRIMARY KEY,O_CUSTKEY int NOT NULL,O_ORDERSTATUS text NOT NULL,O_TOTALPRICE DECIMAL(15, 2) NOT NULL,O_ORDERDATE date NOT NULL,O_ORDERPRIORITY text NOT NULL,O_CLERK text NOT NULL,O_SHIPPRIORITY int NOT NULL,O_COMMENT text NOT NULL
);
CALL set_table_property ('ORDERS', 'segment_key', 'O_ORDERDATE');
CALL set_table_property ('ORDERS', 'colocate_with', 'lineitem');
CALL set_table_property ('ORDERS', 'distribution_key', 'O_ORDERKEY');
CALL set_table_property ('ORDERS', 'bitmap_columns', 'O_ORDERSTATUS,O_ORDERPRIORITY,O_CLERK,O_SHIPPRIORITY');
CALL set_table_property ('ORDERS', 'dictionary_encoding_columns', 'o_comment:off,o_orderstatus,o_orderpriority,o_clerk');
COMMIT;

DROP TABLE IF EXISTS CUSTOMER;BEGIN;
CREATE TABLE CUSTOMER (C_CUSTKEY int NOT NULL PRIMARY KEY,C_NAME text NOT NULL,C_ADDRESS text NOT NULL,C_NATIONKEY int NOT NULL,C_PHONE text NOT NULL,C_ACCTBAL DECIMAL(15, 2) NOT NULL,C_MKTSEGMENT text NOT NULL,C_COMMENT text NOT NULL
);
CALL set_table_property ('CUSTOMER', 'distribution_key', 'C_CUSTKEY');
CALL set_table_property ('CUSTOMER', 'colocate_with', 'lineitem');
CALL set_table_property ('CUSTOMER', 'bitmap_columns', 'C_NATIONKEY,C_MKTSEGMENT');
CALL set_table_property ('CUSTOMER', 'dictionary_encoding_columns', 'c_name:off,c_address:off,c_phone:off,c_comment:off,c_mktsegment');
COMMIT;

DROP TABLE IF EXISTS SUPPLIER;BEGIN;
CREATE TABLE SUPPLIER (S_SUPPKEY int NOT NULL PRIMARY KEY,S_NAME text NOT NULL,S_ADDRESS text NOT NULL,S_NATIONKEY int NOT NULL,S_PHONE text NOT NULL,S_ACCTBAL DECIMAL(15, 2) NOT NULL,S_COMMENT text NOT NULL
);
CALL set_table_property ('SUPPLIER', 'distribution_key', 'S_SUPPKEY');
CALL set_table_property ('SUPPLIER', 'colocate_with', 'lineitem');
CALL set_table_property ('SUPPLIER', 'bitmap_columns', 'S_NATIONKEY');
CALL set_table_property ('SUPPLIER', 'dictionary_encoding_columns', '');
COMMIT;DROP TABLE IF EXISTS NATION;BEGIN;
CREATE TABLE NATION (N_NATIONKEY int NOT NULL PRIMARY KEY,N_NAME text NOT NULL,N_REGIONKEY int NOT NULL,N_COMMENT text NOT NULL
);

CALL set_table_property ('NATION', 'distribution_key', 'N_NATIONKEY');
CALL set_table_property ('NATION', 'colocate_with', 'lineitem');
CALL set_table_property ('NATION', 'bitmap_columns', '');
CALL set_table_property ('NATION', 'dictionary_encoding_columns', '');
COMMIT;DROP TABLE IF EXISTS REGION;BEGIN;
CREATE TABLE REGION (R_REGIONKEY int NOT NULL PRIMARY KEY,R_NAME text NOT NULL,R_COMMENT text
);
CALL set_table_property ('REGION', 'distribution_key', 'R_REGIONKEY');
CALL set_table_property ('REGION', 'colocate_with', 'lineitem');
CALL set_table_property ('REGION', 'bitmap_columns', '');
CALL set_table_property ('REGION', 'dictionary_encoding_columns', '');
COMMIT;

注意事项：

外部表在Hologres中不存储数据，只进行字段映射。通过外部表可以使用Hologres直接调用存储于MaxCompute公共空间MAXCOMPUTE_PUBLIC_DATA的数据。 

3、导入示例数据

• SQL查询的编辑框输入如下语句，单击运行。

INSERT INTO public.customer SELECT * FROM public.odps_customer_10g ;
INSERT INTO public.lineitem SELECT * FROM public.odps_lineitem_10g ;
INSERT INTO public.nation SELECT * FROM public.odps_nation_10g ;
INSERT INTO public.orders SELECT * FROM public.odps_orders_10g ;
INSERT INTO public.part SELECT * FROM public.odps_part_10g ;
INSERT INTO public.partsupp SELECT * FROM public.odps_partsupp_10g ;
INSERT INTO public.region SELECT * FROM public.odps_region_10g ;
INSERT INTO public.supplier SELECT * FROM public.odps_supplier_10g ;vacuum nation;
vacuum region;vacuum supplier;
vacuum supplier;
vacuum customer;
vacuum part;
vacuum partsupp;
vacuum orders;
vacuum lineitem;analyze nation;
analyze region;
analyze lineitem;
analyze orders;
analyze customer;
analyze part;
analyze partsupp;
analyze supplier;
analyze lineitem (l_orderkey,l_partkey,l_suppkey);
analyze orders (o_custkey);
analyze partsupp(ps_partkey,ps_suppkey);

• 在Hologres中，vacuum是一个数据库操作命令，用于回收并释放数据库中不再需要的存储空间。
• 具体而言，vacuum 命令的作用通常包括：

• Analyze 也是一个数据库操作命令，用于收集统计信息，以帮助数据库系统优化查询计划。通过分析表的数据分布和结构，数据库系统可以更好地选择执行计划，提高查询性能。
• 它通常执行以下操作： 

4、查询表中数据

selectl_returnflag,l_linestatus,sum(l_quantity) as sum_qty,sum(l_extendedprice) as sum_base_price,sum(l_extendedprice * (1 - l_discount)) as sum_disc_price,sum(l_extendedprice * (1 - l_discount) * (1 + l_tax)) as sum_charge,avg(l_quantity) as avg_qty,avg(l_extendedprice) as avg_price,avg(l_discount) as avg_disc,count(*) as count_order
From lineitem
Where l_shipdate <= date '1998-12-01' - interval '120' day
group by l_returnflag, l_linestatus
order byl_returnflag,l_linestatus;

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