设置存储引擎

存储引擎会对数据库整体效率和性能具有巨大影响，请根据实际需求选择适当的存储引擎。用户可使用WITH ( [ORIENTATION | STORAGE_TYPE] [= value] [, ... ] )为表或索引指定一个可选的存储参数。参数的详细描述如下所示：

如果ORIENTATION指定为ROW，且STORAGE_TYPE为空的情况下创建出的表类型取决于GUC参数enable_default_ustore_table（取值为on/off，默认情况为on，参数详情请参见《管理员指南》中“配置运行参数 > GUC参数说明”章节）：如果参数设置为on，创建出的表为Ustore类型；如果为off，创建出的表为Astore类型。

具体示例如下：

gaussdb=# CREATE TABLE TEST(a int);
gaussdb=# \d+ test
                         Table "public.test"
 Column |  Type   | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------
 a      | integer |           | plain   |              |
Has OIDs: no
Options: orientation=row, compression=no, storage_type=USTORE, segment=off

gaussdb=# CREATE TABLE TEST1(a int) with(orientation=row, storage_type=ustore);
gaussdb=# \d+ test1
Table "public.test1"
 Column |  Type   | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------
 a      | integer |           | plain   |              |
Has OIDs: no
Options: orientation=row, storage_type=ustore, compression=no, segment=off

gaussdb=# CREATE TABLE TEST2(a int) with(orientation=row, storage_type=astore);
gaussdb=# \d+ test2
Table "public.test2"
 Column |  Type   | Modifiers | Storage | Stats target | Description
--------+---------+-----------+---------+--------------+-------------
 a      | integer |           | plain   |              |
Has OIDs: no
Options: orientation=row, storage_type=astore, compression=no
gaussdb=# CREATE TABLE test4(a int) with(orientation=row);
gaussdb=# \d+
                                                       List of relations
 Schema | Name  | Type  |   Owner   |  Size   |                             Storage                              | Description
--------+-------+-------+-----------+---------+------------------------------------------------------------------+-------------
 public | test  | table | z7ee88f3a | 0 bytes | {orientation=row,compression=no,storage_type=USTORE,segment=off} |
 public | test1 | table | z7ee88f3a | 0 bytes | {orientation=row,storage_type=ustore,compression=no,segment=off} |
 public | test2 | table | z7ee88f3a | 0 bytes | {orientation=row,storage_type=astore,compression=no}             |
 public | test3 | table | z7ee88f3a | 16 kB   | {orientation=column,storage_type=astore,compression=low}         |
 public | test4 | table | z7ee88f3a | 0 bytes | {orientation=row,compression=no,storage_type=USTORE,segment=off} |
(5 rows)

gaussdb=# show enable_default_ustore_table;
 enable_default_ustore_table
-----------------------------
 on
(1 row)

gaussdb=#  DROP TABLE test;
gaussdb=#  DROP TABLE test1;
gaussdb=#  DROP TABLE test2;
gaussdb=#  DROP TABLE test4;