使用Ustore进行测试

创建Ustore表

使用CREATE TABLE语句创建Ustore表。

gaussdb=# CREATE TABLE ustore_table(a INT PRIMARY KEY, b CHAR (20)) WITH (STORAGE_TYPE=USTORE);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "ustore_table_pkey" for table "ustore_table"
CREATE TABLE
gaussdb=# \d+ ustore_table
Table "public.ustore_table"
Column |     Type      | Modifiers | Storage  | Stats target | Description
--------+---------------+-----------+----------+--------------+-------------
a      | integer       | not null  | plain    |              |
b      | character(20) |           | extended |              |
Indexes:
"ustore_table_pkey" PRIMARY KEY, ubtree (a) WITH (storage_type=USTORE) TABLESPACE pg_default
Has OIDs: no
Options: orientation=row, storage_type=ustore, compression=no

为Ustore表创建索引

Ustore当前仅支持B-tree类型的多版本索引，在一些场景中，为了区别于Astore的B-tree索引，也会将Ustore表的多版本B-tree索引称为UB-tree（Ustore B-tree，UB-tree介绍详见Index章节）。用户可以参照以下方式使用CREATE INDEX语句为Ustore表的 “a” 属性创建一个UB-tree索引。

Ustore表不指定创建索引类型，默认创建的是UB-tree索引：

gaussdb=# CREATE INDEX UB-tree_index ON ustore_table(a);
CREATE INDEX
gaussdb=# \d+ ustore_table
Table "public.ustore_table"
Column |     Type      | Modifiers | Storage  | Stats target | Description
--------+---------------+-----------+----------+--------------+-------------
a      | integer       | not null  | plain    |              |
b      | character(20) |           | extended |              |
Indexes:
"ustore_table_pkey" PRIMARY KEY, ubtree (a) WITH (storage_type=USTORE) TABLESPACE pg_default
"ubtree_index" ubtree (a) WITH (storage_type=USTORE) TABLESPACE pg_default
Has OIDs: no
Options: orientation=row, storage_type=ustore, compression=no