PolarDB-X的AUTO模式數據庫的分區表允許用戶可以通過MySQL分區選擇語法直接讀寫某個分區的數據。

SQL語法

指定分區名進行SELECT操作

SELECT ... FROM tbl_name [PARTITION ( part_name[, part_name, ...] )]

指定分區名進行UPDATE操作

UPDATE tbl_name [PARTITION ( part_name[, part_name, ...] )] SET ... WHERE ...

指定分區名進行DELETE操作

DELETE FROM tbl_name [PARTITION ( part_name[, part_name, ...] )] WHERE ...

選擇一級分區

示例1：直接指定分區表的一個或多個一級分區進行查詢

CREATE TABLE tb_k(
    ->  id bigint not null auto_increment, 
    ->  bid int, 
    ->  name varchar(30),
    ->  birthday datetime not null,
    ->  primary key(id)
    -> ) 
    -> PARTITION BY KEY(id, bid) 
    -> PARTITIONS 8;
Query OK, 0 rows affected (2.06 sec)

explain SELECT * FROM tb_k PARTITION( p1,p2 );
+-----------------------------------------------------------------------------------------------------------------------+
| LOGICAL EXECUTIONPLAN                                                                                                 |
+-----------------------------------------------------------------------------------------------------------------------+
| Gather(concurrent=true)                                                                                               |
|   LogicalView(tables="tb_k[p1,p2]", shardCount=2, sql="SELECT `id`, `bid`, `name`, `birthday` FROM `tb_k` AS `tb_k`") |
| HitCache:false                                                                                                        |
| Source:PLAN_CACHE                                                                                                     |
| TemplateId: e210fe50                                                                                                  |
+-----------------------------------------------------------------------------------------------------------------------+
5 rows in set (0.05 sec)

示例2：直接指定分區表的一個或多個一級分區數據刪除

CREATE TABLE tb_k(
    ->  id bigint not null auto_increment, 
    ->  bid int, 
    ->  name varchar(30),
    ->  birthday datetime not null,
    ->  primary key(id)
    -> ) 
    -> PARTITION BY KEY(id, bid) 
    -> PARTITIONS 8;
Query OK, 0 rows affected (3.59 sec)

explain DELETE FROM tb_k PARTITION( p1,p2 );
+---------------------------------------------------------------------------------+
| LOGICAL EXECUTIONPLAN                                                           |
+---------------------------------------------------------------------------------+
| LogicalModifyView(tables="tb_k[p1,p2]", shardCount=2, sql="DELETE FROM `tb_k`") |
| HitCache:false                                                                  |
| Source:PLAN_CACHE                                                               |
| TemplateId: 19bd2adf                                                            |
+---------------------------------------------------------------------------------+

選擇二級分區

示例3：直接指定分區表的一個或多個一級分區或二級分區進行查詢

CREATE TABLE tb_k_k_tp(
    ->  id bigint not null auto_increment, 
    ->  bid int, 
    ->  name varchar(30),
    ->  birthday datetime not null,
    ->  primary key(id)
    -> ) 
    -> PARTITION BY KEY(bid,name) 
    -> PARTITIONS 2
    -> SUBPARTITION BY KEY(id) 
    -> SUBPARTITIONS 4;
Query OK, 0 rows affected (1.94 sec)

explain SELECT * FROM tb_k_k_tp PARTITION( p1sp1,p1sp2 )/*指定兩個二級分區*/;
+--------------------------------------------------------------------------------------------------------------------------------------------+
| LOGICAL EXECUTIONPLAN                                                                                                                      |
+--------------------------------------------------------------------------------------------------------------------------------------------+
| Gather(concurrent=true)                                                                                                                    |
|   LogicalView(tables="tb_k_k_tp[p1sp1,p1sp2]", shardCount=2, sql="SELECT `id`, `bid`, `name`, `birthday` FROM `tb_k_k_tp` AS `tb_k_k_tp`") |
| HitCache:false                                                                                                                             |
| Source:PLAN_CACHE                                                                                                                          |
| TemplateId: 38bba74d                                                                                                                       |
+--------------------------------------------------------------------------------------------------------------------------------------------+
5 rows in set (0.03 sec)

explain SELECT * FROM tb_k_k_tp PARTITION( p1,p2sp2 )/*指定一個一級分區，一個二級分區*/;
+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
| LOGICAL EXECUTIONPLAN                                                                                                                                        |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Gather(concurrent=true)                                                                                                                                      |
|   LogicalView(tables="tb_k_k_tp[p1sp1,p1sp2,p1sp3,p1sp4,p2sp2]", shardCount=5, sql="SELECT `id`, `bid`, `name`, `birthday` FROM `tb_k_k_tp` AS `tb_k_k_tp`") |
| HitCache:false                                                                                                                                               |
| Source:PLAN_CACHE                                                                                                                                            |
| TemplateId: dbc4cb56                                                                                                                                         |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
5 rows in set (0.01 sec)