Implementation:Apache Dolphinscheduler DataSourceClientProvider Cache Lifecycle

Knowledge Sources	Apache DolphinScheduler Guava Cache HikariCP
Domains	Connection_Management, Resource_Management
Last Updated	2026-02-10 00:00 GMT

Overview

Concrete tool for managing connection pool lifecycle using DataSourceClientProvider's Guava Cache with RemovalListener and BasePooledDataSourceClient.close() for HikariCP pool shutdown.

Description

'DataSourceClientProvider at L47-64 configures a Guava Cache with expireAfterAccess using DataSourceConstants.DATASOURCE_CLIENT_EXPIRE_SECONDS. The RemovalListener<String, PooledDataSourceClient> calls client.close() on eviction. BasePooledDataSourceClient.close() at L80-87 delegates to HikariDataSource.close() which terminates all idle and in-use connections. Configuration constants from DataSourceConstants control pool sizing: DATASOURCE_POOL_MAX_ACTIVE (maximum pool size), DATASOURCE_POOL_MIN_IDLE (minimum idle connections).

Usage

Automatic. No manual cleanup required. The cache eviction handles pool lifecycle transparently.

Code Reference

Source Location

Repository: dolphinscheduler
File: dolphinscheduler-datasource-plugin/dolphinscheduler-datasource-api/src/main/java/org/apache/dolphinscheduler/plugin/datasource/api/plugin/DataSourceClientProvider.java (L47-64)
File: dolphinscheduler-datasource-plugin/dolphinscheduler-datasource-api/src/main/java/org/apache/dolphinscheduler/plugin/datasource/api/client/BasePooledDataSourceClient.java (L80-87)

Signature

@Component
public class DataSourceClientProvider {
    // Guava cache with TTL-based eviction and cleanup listener
    private static final Cache<String, PooledDataSourceClient>
        POOLED_DATASOURCE_CLIENT_CACHE = CacheBuilder.newBuilder()
            .expireAfterAccess(
                DataSourceConstants.DATASOURCE_CLIENT_EXPIRE_SECONDS,
                TimeUnit.SECONDS)
            .removalListener((RemovalListener<String, PooledDataSourceClient>)
                notification -> {
                    if (notification.getValue() != null) {
                        notification.getValue().close();
                    }
                })
            .build();
}

public class BasePooledDataSourceClient {
    @Override
    public void close() {
        if (hikariDataSource != null) {
            hikariDataSource.close();  // releases all connections
        }
    }
}

Import

import org.apache.dolphinscheduler.plugin.datasource.api.plugin.DataSourceClientProvider;
import org.apache.dolphinscheduler.plugin.datasource.api.constants.DataSourceConstants;

I/O Contract

Inputs

Name	Type	Required	Description
Cache access patterns	get/put	Automatic	TTL refreshed on each access
DATASOURCE_CLIENT_EXPIRE_SECONDS	long	Configuration	Cache TTL in seconds
DATASOURCE_POOL_MAX_ACTIVE	int	Configuration	Maximum HikariCP pool size
DATASOURCE_POOL_MIN_IDLE	int	Configuration	Minimum idle connections in pool

Outputs

Name	Type	Description
Pool cleanup	Side effect	HikariDataSource.close() called on eviction
Connection release	Side effect	All pooled JDBC connections released

Usage Examples

Automatic Lifecycle

// Access 1: Pool created for MySQL datasource "ds_1"
Connection conn1 = provider.getPooledConnection(DbType.MYSQL, param);
// HikariCP pool created, cached in Guava cache

// Access 2 (within TTL): Pool reused
Connection conn2 = provider.getPooledConnection(DbType.MYSQL, param);
// Same HikariCP pool, TTL refreshed

// No access for DATASOURCE_CLIENT_EXPIRE_SECONDS...
// Guava triggers eviction:
//   RemovalListener -> client.close() -> hikariDataSource.close()
//   All connections released back to database server

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