CREATE READWRITE_SPLITTING RULE

Description

The CREATE READWRITE_SPLITTING RULE syntax is used to create a read/write splitting rule.

Syntax

Grammar Railroad diagram

  1. CreateReadwriteSplittingRule ::=
  2.   'CREATE' 'READWRITE_SPLITTING' 'RULE' ifNotExists? readwriteSplittingDefinition (',' readwriteSplittingDefinition)*
  4. ifNotExists ::=
  5.   'IF' 'NOT' 'EXISTS'
  7. readwriteSplittingDefinition ::=
  8.   ruleName '(' dataSourceDefinition (',' transactionalReadQueryStrategyDefinition)? (',' loadBalancerDefinition)? ')'
  10. dataSourceDefinition ::=
  11.     'WRITE_STORAGE_UNIT' '=' writeStorageUnitName ',' 'READ_STORAGE_UNITS' '(' storageUnitName (',' storageUnitName)* ')' 
  13. transactionalReadQueryStrategyDefinition ::=
  14.     'TRANSACTIONAL_READ_QUERY_STRATEGY' '=' transactionalReadQueryStrategyType
  16. loadBalancerDefinition ::=
  17.     'TYPE' '(' 'NAME' '=' loadBalancerType (',' propertiesDefinition)? ')'
  19. ruleName ::=
  20.   identifier
  22. writeStorageUnitName ::=
  23.   identifier
  25. storageUnitName ::=
  26.   identifier
  28. transactionalReadQueryStrategyType ::=
  29.   string
  31. loadBalancerType ::=
  32.   string
  34. propertiesDefinition ::=
  35.   'PROPERTIES' '(' key '=' value (',' key '=' value)* ')'
  37. key ::=
  38.   string
  40. value ::=
  41.   literal

Note

  • transactionalReadQueryStrategyType specifies the routing strategy for read query within a transaction, please refer to YAML configuration;
  • loadBalancerType specifies the load balancing algorithm type, please refer to Load Balance Algorithm;
  • Duplicate ruleName will not be created;
  • ifNotExists clause used to avoid the Duplicate readwrite_splitting rule error.

Example

Create a read/write splitting rule

  1. CREATE READWRITE_SPLITTING RULE ms_group_0 (
  2.     WRITE_STORAGE_UNIT=write_ds,
  3.     READ_STORAGE_UNITS(read_ds_0,read_ds_1),
  4.     TYPE(NAME="random")
  5. );

Create read/write splitting rule with the ifNotExists clause

  • read/write splitting rule
  1. CREATE READWRITE_SPLITTING RULE IF NOT EXISTS ms_group_0 (
  2.     WRITE_STORAGE_UNIT=write_ds,
  3.     READ_STORAGE_UNITS(read_ds_0,read_ds_1),
  4.     TYPE(NAME="random")
  5. );

Reserved words

CREATE, READWRITE_SPLITTING, RULE, WRITE_STORAGE_UNIT, READ_STORAGE_UNITS , TYPE, NAME, PROPERTIES, TRUE, FALSE