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ALTER READWRITE_SPLITTING RULE

描述

ALTER READWRITE_SPLITTING RULE 语法用于修改读写分离规则

语法定义

AlterReadwriteSplittingRule ::=
  'ALTER' 'READWRITE_SPLITTING' 'RULE' readwriteSplittingDefinition ( ',' readwriteSplittingDefinition )*

readwriteSplittingDefinition ::=
  ruleName '(' ( staticReadwriteSplittingDefinition | dynamicReadwriteSplittingDefinition ) ( ',' loadBalancerDefinition )? ')'

staticReadwriteSplittingDefinition ::=
    'WRITE_RESOURCE' '=' writeResourceName ',' 'READ_RESOURCES' '(' ruleName (',' ruleName)* ')'

dynamicReadwriteSplittingDefinition ::=
    'AUTO_AWARE_RESOURCE' '=' resourceName ( ',' 'WRITE_DATA_SOURCE_QUERY_ENABLED' '=' ('TRUE' | 'FALSE') )?

loadBalancerDefinition ::=
    'TYPE' '(' 'NAME' '=' loadBalancerType ( ',' 'PROPERTIES' '(' 'key' '=' 'value' ( ',' 'key' '=' 'value' )* ')' )? ')'

ruleName ::=
  identifier

writeResourceName ::=
  identifier

resourceName ::=
  identifier
    
loadBalancerType ::=
  string

补充说明

  • 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；

示例

修改静态读写分离规则

ALTER READWRITE_SPLITTING RULE ms_group_0 (
    WRITE_RESOURCE=write_ds,
    READ_RESOURCES(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

修改动态读写分离规则

ALTER READWRITE_SPLITTING RULE ms_group_1 (
    AUTO_AWARE_RESOURCE=group_0,
    WRITE_DATA_SOURCE_QUERY_ENABLED=false,
    TYPE(NAME="random",PROPERTIES("read_weight"="2:1"))
);

保留字

ALTER、READWRITE_SPLITTING、RULE、WRITE_RESOURCE、READ_RESOURCES、AUTO_AWARE_RESOURCE、WRITE_DATA_SOURCE_QUERY_ENABLED 、TYPE、NAME、PROPERTIES、TRUE、FALSE

相关链接