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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

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