Sharding

Definition

Sharding Table Rule

CREATE SHARDING TABLE RULE shardingTableRuleDefinition [, shardingTableRuleDefinition] ...

CREATE DEFAULT SHARDING shardingScope STRATEGY (shardingStrategy)

ALTER SHARDING TABLE RULE shardingTableRuleDefinition [, shardingTableRuleDefinition] ...

DROP SHARDING TABLE RULE tableName [, tableName] ...

CREATE SHARDING ALGORITHM shardingAlgorithmDefinition [,  shardingAlgorithmDefinition] ...

DROP SHARDING ALGORITHM algorithmName [, algorithmName] ...

shardingTableRuleDefinition:
    shardingAutoTableRule | shardingTableRule
   
shardingAutoTableRule:
    tableName(resources (COMMA shardingColumn)? (COMMA algorithmDefinition)? (COMMA keyGenerateStrategy)?)
    
shardingTableRule:
    tableName(dataNodes (COMMA  databaseStrategy)? (COMMA tableStrategy)? (COMMA keyGenerateStrategy)?)

resources:
    RESOURCES(resource [, resource] ...)

dataNodes:
    DATANODES(dataNode [, dataNode] ...)

resource:
    resourceName | inlineExpression

dataNode:
    resourceName | inlineExpression

shardingColumn:
    SHARDING_COLUMN=columnName

algorithmDefinition:
    TYPE(NAME=shardingAlgorithmType [, PROPERTIES([algorithmProperties])])

keyGenerateStrategy:
    GENERATED_KEY(COLUMN=columnName, strategyDefinition)

shardingScope:
    DATABASE | TABLE

databaseStrategy:
    DATABASE_STRATEGY(shardingStrategy)

tableStrategy:
    TABLE_STRATEGY(shardingStrategy)

shardingStrategy:
    TYPE=strategyType, shardingColumn, shardingAlgorithm

shardingColumn:
    SHARDING_COLUMN=columnName
    
shardingAlgorithm:
    SHARDING_ALGORITHM=shardingAlgorithmName

strategyDefinition:
    TYPE(NAME=keyGenerateStrategyType [, PROPERTIES([algorithmProperties])])

shardingAlgorithmDefinition:
    shardingAlgorithmName(algorithmDefinition)

algorithmProperties:
    algorithmProperty [, algorithmProperty] ...

algorithmProperty:
    key=value
  • RESOURCES needs to use data source resources managed by RDL
  • shardingAlgorithmType specifies the type of automatic sharding algorithm, please refer to Auto Sharding Algorithm
  • keyGenerateStrategyType specifies the distributed primary key generation strategy, please refer to Key Generate Algorithm
  • Duplicate tableName will not be created
  • shardingAlgorithm can be reused by different Sharding Table Rule, so when executing DROP SHARDING TABLE RULE, the corresponding shardingAlgorithm will not be removed
  • To remove shardingAlgorithm, please execute DROP SHARDING ALGORITHM
  • strategyType specifies the sharding strategy，please refer toSharding Strategy

Sharding Binding Table Rule

CREATE SHARDING BINDING TABLE RULES bindTableRulesDefinition [, bindTableRulesDefinition] ...

ALTER SHARDING BINDING TABLE RULES bindTableRulesDefinition [, bindTableRulesDefinition] ...

DROP SHARDING BINDING TABLE RULES bindTableRulesDefinition [, bindTableRulesDefinition] ...

bindTableRulesDefinition:
    (tableName [, tableName] ... )
  • ALTER will overwrite the binding table configuration in the database with the new configuration

Sharding Broadcast Table Rule

CREATE SHARDING BROADCAST TABLE RULES (tableName [, tableName] ... )

ALTER SHARDING BROADCAST TABLE RULES (tableName [, tableName] ... )

DROP SHARDING BROADCAST TABLE RULES
  • ALTER will overwrite the broadcast table configuration in the database with the new configuration

Example

Sharding Table Rule

CREATE SHARDING TABLE RULE t_order (
RESOURCES(resource_0,resource_1),
SHARDING_COLUMN=order_id,
TYPE(NAME=hash_mod,PROPERTIES("sharding-count"=4)),
GENERATED_KEY(COLUMN=another_id,TYPE(NAME=snowflake,PROPERTIES("worker-id"=123)))
),t_order_item (
DATANODES("resource_${0..1}.t_order${0..1}"),
DATABASE_STRATEGY(TYPE=standard,SHARDING_COLUMN=user_id,SHARDING_ALGORITHM=database_inline),
TABLE_STRATEGY(TYPE=standard,SHARDING_COLUMN=order_id,SHARDING_ALGORITHM=database_inline),
GENERATED_KEY(COLUMN=another_id,TYPE(NAME=snowflake,PROPERTIES("worker-id"=123)))
);

ALTER SHARDING TABLE RULE t_order (
RESOURCES(resource_0,resource_1),
SHARDING_COLUMN=order_id,
TYPE(NAME=hash_mod,PROPERTIES("sharding-count"=10)),
GENERATED_KEY(COLUMN=another_id,TYPE(NAME=snowflake,PROPERTIES("worker-id"=123)))
),t_order_item (
DATANODES("resource_0.t_order${0..1}"),
DATABASE_STRATEGY(TYPE=standard,SHARDING_COLUMN=user_id,SHARDING_ALGORITHM=database_inline),
TABLE_STRATEGY(TYPE=standard,SHARDING_COLUMN=order_id,SHARDING_ALGORITHM=database_inline),
GENERATED_KEY(COLUMN=another_id,TYPE(NAME=uuid,PROPERTIES("worker-id"=123)))
);

DROP SHARDING TABLE RULE t_order, t_order_item;

CREATE DEFAULT SHARDING DATABASE STRATEGY (
TYPE = standard,SHARDING_COLUMN=order_id,SHARDING_ALGORITHM=algorithmsName
);

CREATE SHARDING ALGORITHM algorithmName (
TYPE(NAME=hash_mod,PROPERTIES("algorithm-expression"="t_order_${order_id % 2}"))
);

DROP SHARDING ALGORITHM t_order_hash_mod;

Sharding Binding Table Rule

CREATE SHARDING BINDING TABLE RULES (t_order,t_order_item),(t_1,t_2);

ALTER SHARDING BINDING TABLE RULES (t_order,t_order_item);

DROP SHARDING BINDING TABLE RULES;

DROP SHARDING BINDING TABLE RULES (t_order,t_order_item);

Sharding Broadcast Table Rule

CREATE SHARDING BROADCAST TABLE RULES (t_b,t_a);

ALTER SHARDING BROADCAST TABLE RULES (t_b,t_a,t_3);

DROP SHARDING BROADCAST TABLE RULES;