CREATE READWRITE_SPLITTING RULE

Description

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

Syntax

CreateReadwriteSplittingRule ::=
  'CREATE' 'READWRITE_SPLITTING' 'RULE' ifNotExists? readwriteSplittingDefinition (',' readwriteSplittingDefinition)*

ifNotExists ::=
  'IF' 'NOT' 'EXISTS'

readwriteSplittingDefinition ::=
  ruleName '(' dataSourceDefinition (',' transactionalReadQueryStrategyDefinition)? (',' loadBalancerDefinition)? ')'

dataSourceDefinition ::=
    'WRITE_STORAGE_UNIT' '=' writeStorageUnitName ',' 'READ_STORAGE_UNITS' '(' storageUnitName (',' storageUnitName)* ')' 

transactionalReadQueryStrategyDefinition ::=
    'TRANSACTIONAL_READ_QUERY_STRATEGY' '=' transactionalReadQueryStrategyType

loadBalancerDefinition ::=
    'TYPE' '(' 'NAME' '=' algorithmType (',' propertiesDefinition)? ')'

ruleName ::=
  identifier

writeStorageUnitName ::=
  identifier

storageUnitName ::=
  identifier

transactionalReadQueryStrategyType ::=
  string

algorithmType ::=
  string

propertiesDefinition ::=
  'PROPERTIES' '(' key '=' value (',' key '=' value)* ')'

key ::=
  string

value ::=
  literal

Note

transactionalReadQueryStrategyType specifies the routing strategy for read query within a transaction, please refer to YAML configuration;
algorithmType 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

CREATE READWRITE_SPLITTING RULE ms_group_0 (
    WRITE_STORAGE_UNIT=write_ds,
    READ_STORAGE_UNITS(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

Create read/write splitting rule with the `ifNotExists` clause

read/write splitting rule

CREATE READWRITE_SPLITTING RULE IF NOT EXISTS ms_group_0 (
    WRITE_STORAGE_UNIT=write_ds,
    READ_STORAGE_UNITS(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

Reserved words

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