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SQL-federation

Background

This function is an experimental one and is currently not suitable for use in core system production environments. When multiple tables in a join query are distributed across different database instances, enabling federated query allows for cross-database join queries, as well as subqueries.

Parameters

Class: org.apache.shardingsphere.sqlfederation.config.SQLFederationRuleConfiguration

Attributes:

name DataType Description Default Value
allQueryUseSQLFederation boolean all query use SQL federation configuration -
executionPlanCache org.apache.shardingsphere.sqlfederation.config.SQLFederationCacheOption execution plan cache configuration -
providerType String SQL federation provider type; NONE disables federation NONE

Cache option Configuration

Class: org.apache.shardingsphere.sqlfederation.config.SQLFederationCacheOption

Attributes:

name DataType Description Default Value
initialCapacity int Initial capacity of local cache execution plan local cache default value of 2000
maximumSize long Maximum capacity of local cache execution plan local cache maximum default value 65535

Sample

private SQLFederationRuleConfiguration createSQLFederationRuleConfiguration() {
    SQLFederationCacheOption executionPlanCache = new SQLFederationCacheOption(2000, 65535L);
    return new SQLFederationRuleConfiguration(false, executionPlanCache, "CALCITE");
}