CREATE SHADOW RULE 语法用于创建影子库压测规则。
CreateShadowRule ::=
  'CREATE' 'SHADOW' 'RULE' ifNotExists? shadowRuleDefinition (',' shadowRuleDefinition)*
ifNotExists ::=
  'IF' 'NOT' 'EXISTS'
shadowRuleDefinition ::=
  ruleName '(' storageUnitMapping shadowTableRule (',' shadowTableRule)* ')'
    
storageUnitMapping ::=
  'SOURCE' '=' storageUnitName ',' 'SHADOW' '=' storageUnitName
shadowTableRule ::=
  tableName '(' shadowAlgorithm ')'
    
shadowAlgorithm ::=
  'TYPE' '(' 'NAME' '=' shadowAlgorithmType ',' propertiesDefinition ')'
ruleName ::=
  identifier
storageUnitName ::=
  identifier
tableName ::=
  identifier
algorithmName ::=
  identifier
shadowAlgorithmType ::=
  string
propertiesDefinition ::=
  'PROPERTIES' '(' key '=' value (',' key '=' value)* ')'
key ::=
  string
value ::=
  literal
ruleName 无法被创建;storageUnitMapping 指定源数据库和影子库的映射关系,需使用 RDL 管理的 STORAGE UNIT
,请参考 存储单元;shadowAlgorithm 可同时作用于多个 shadowTableRule;algorithmName 会根据 ruleName、tableName 和 shadowAlgorithmType 自动生成;shadowAlgorithmType 目前支持 VALUE_MATCH、REGEX_MATCH 和 SQL_HINT;ifNotExists 子句用于避免出现 Duplicate shadow rule 错误。CREATE SHADOW RULE shadow_rule(
  SOURCE=demo_ds,
  SHADOW=demo_ds_shadow,
  t_order(TYPE(NAME="SQL_HINT")), 
  t_order_item(TYPE(NAME="VALUE_MATCH", PROPERTIES("operation"="insert","column"="user_id", "value"='1')))
);
ifNotExists 子句创建影子库压测规则CREATE SHADOW RULE IF NOT EXISTS shadow_rule(
  SOURCE=demo_ds,
  SHADOW=demo_ds_shadow,
  t_order(TYPE(NAME="SQL_HINT")), 
  t_order_item(TYPE(NAME="VALUE_MATCH", PROPERTIES("operation"="insert","column"="user_id", "value"='1')))
);
CREATE、SHADOW、RULE、SOURCE、SHADOW、TYPE、NAME、PROPERTIES
