CREATE READWRITE_SPLITTING RULE

描述

CREATE READWRITE_SPLITTING RULE 语法用于创建读写分离规则

语法定义

语法 铁路图

CreateReadwriteSplittingRule ::=
  'CREATE' 'READWRITE_SPLITTING' 'RULE' ifNotExists? readwriteSplittingDefinition (',' readwriteSplittingDefinition)*
ifNotExists ::=
  'IF' 'NOT' 'EXISTS'
readwriteSplittingDefinition ::=
  ruleName '(' (staticReadwriteSplittingDefinition | dynamicReadwriteSplittingDefinition) (',' loadBalancerDefinition)? ')'
staticReadwriteSplittingDefinition ::=
    'WRITE_STORAGE_UNIT' '=' writeStorageUnitName ',' 'READ_STORAGE_UNITS' '(' storageUnitName (',' storageUnitName)* ')'
dynamicReadwriteSplittingDefinition ::=
    'AUTO_AWARE_RESOURCE' '=' resourceName
loadBalancerDefinition ::=
    'TYPE' '(' 'NAME' '=' loadBalancerType (',' propertiesDefinition)? ')'
ruleName ::=
  identifier
writeStorageUnitName ::=
  identifier
storageUnitName ::=
  identifier
resourceName ::=
  identifier
loadBalancerType ::=
  string
propertiesDefinition ::=
  'PROPERTIES' '(' key '=' value (',' key '=' value)* ')'
key ::=
  string
value ::=
  literal

补充说明

• 支持创建静态读写分离规则和动态读写分离规则；
• 动态读写分离规则依赖于数据库发现规则；
• loadBalancerType 指定负载均衡算法类型，请参考负载均衡算法；
• 重复的 ruleName 将无法被创建；
• ifNotExists 子句用于避免出现 Duplicate readwrite_splitting rule 错误。

示例

创建静态读写分离规则

CREATE READWRITE_SPLITTING RULE ms_group_0 (
    WRITE_STORAGE_UNIT=write_ds,
    READ_STORAGE_UNITS(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

创建动态读写分离规则

CREATE READWRITE_SPLITTING RULE ms_group_1 (
    AUTO_AWARE_RESOURCE=group_0
    TYPE(NAME="random")
);

使用 ifNotExists 子句创建读写分离规则

• 静态读写分离规则

CREATE READWRITE_SPLITTING RULE IF NOT EXISTS ms_group_0 (
    WRITE_STORAGE_UNIT=write_ds,
    READ_STORAGE_UNITS(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

• 动态读写分离规则

CREATE READWRITE_SPLITTING RULE IF NOT EXISTS ms_group_1 (
    AUTO_AWARE_RESOURCE=group_0
    TYPE(NAME="random")
);

保留字

CREATE、READWRITE_SPLITTING、RULE、WRITE_STORAGE_UNIT、READ_STORAGE_UNITS、AUTO_AWARE_RESOURCE 、TYPE、NAME、PROPERTIES、TRUE、FALSE

相关链接

• 保留字
• 负载均衡算法