ALTER READWRITE_SPLITTING RULE

Description

The ALTER READWRITE_SPLITTING RULE syntax is used to alter a readwrite-splitting rule.

Syntax

Grammar Railroad diagram

  1. AlterReadwriteSplittingRule ::=
  2.   'ALTER' 'READWRITE_SPLITTING' 'RULE' readwriteSplittingDefinition (',' readwriteSplittingDefinition)*
  4. readwriteSplittingDefinition ::=
  5.   ruleName '(' dataSourceDefinition (',' transactionalReadQueryStrategyDefinition)? (',' loadBalancerDefinition)? ')'
  7. dataSourceDefinition ::=
  8.     'WRITE_STORAGE_UNIT' '=' writeStorageUnitName ',' 'READ_STORAGE_UNITS' '(' storageUnitName (',' storageUnitName)* ')' 
  10. transactionalReadQueryStrategyDefinition ::=
  11.     'TRANSACTIONAL_READ_QUERY_STRATEGY' '=' transactionalReadQueryStrategyType
  13. loadBalancerDefinition ::=
  14.     'TYPE' '(' 'NAME' '=' loadBalancerType (',' propertiesDefinition)? ')'
  16. ruleName ::=
  17.   identifier
  19. writeStorageUnitName ::=
  20.   identifier
  22. storageUnitName ::=
  23.   identifier
  25. transactionalReadQueryStrategyType ::=
  26.   string
  28. loadBalancerType ::=
  29.   string
  31. propertiesDefinition ::=
  32.   'PROPERTIES' '(' key '=' value (',' key '=' value)* ')'
  34. key ::=
  35.   string
  37. value ::=
  38.   literal

Supplement

  • 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.

Example

Alter a readwrite-splitting rule

  1. ALTER 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. );

Reserved word

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