ALTER READWRITE_SPLITTING RULE

Description

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

Syntax

AlterReadwriteSplittingRule ::=
  'ALTER' 'READWRITE_SPLITTING' 'RULE' readwriteSplittingDefinition ( ',' readwriteSplittingDefinition )*
readwriteSplittingDefinition ::=
  ruleName '(' ( staticReadwriteSplittingDefinition | dynamicReadwriteSplittingDefinition ) ( ',' loadBalancerDefinition )? ')'
staticReadwriteSplittingDefinition ::=
    'WRITE_RESOURCE' '=' writeResourceName ',' 'READ_RESOURCES' '(' ruleName (',' ruleName)* ')'
dynamicReadwriteSplittingDefinition ::=
    'AUTO_AWARE_RESOURCE' '=' resourceName ( ',' 'WRITE_DATA_SOURCE_QUERY_ENABLED' '=' ('TRUE' | 'FALSE') )?
loadBalancerDefinition ::=
    'TYPE' '(' 'NAME' '=' loadBalancerType ( ',' 'PROPERTIES' '(' 'key' '=' 'value' ( ',' 'key' '=' 'value' )* ')' )? ')'
ruleName ::=
  identifier
writeResourceName ::=
  identifier
resourceName ::=
  identifier
loadBalancerType ::=
  string

Supplement

• Dynamic readwrite-splitting rules rely on database discovery rules;
• loadBalancerType specifies the load balancing algorithm type, please refer to Load Balance Algorithm;

Example

Alter a statics readwrite splitting rule

ALTER READWRITE_SPLITTING RULE ms_group_0 (
    WRITE_RESOURCE=write_ds,
    READ_RESOURCES(read_ds_0,read_ds_1),
    TYPE(NAME="random")
);

Alter a dynamic readwrite splitting rule

ALTER READWRITE_SPLITTING RULE ms_group_1 (
    AUTO_AWARE_RESOURCE=group_0,
    WRITE_DATA_SOURCE_QUERY_ENABLED=false,
    TYPE(NAME="random",PROPERTIES("read_weight"="2:1"))
);

Reserved word

ALTER, READWRITE_SPLITTING, RULE, WRITE_RESOURCE, READ_RESOURCES, AUTO_AWARE_RESOURCE , WRITE_DATA_SOURCE_QUERY_ENABLED, TYPE, NAME, PROPERTIES, TRUE, FALSE

Related links

• Reserved word