Скачать или смотреть Understanding oracle.net.keepAlive in Connection Pooling: Hikari CP vs Oracle UCP

Explore the differences between `oracle.net.keepAlive` setting in Hikari CP and Oracle UCP. Learn how to handle idle connections effectively for optimal database performance.
---
This video is based on the question https://stackoverflow.com/q/77806932/ asked by the user 'tomas' ( https://stackoverflow.com/u/992470/ ) and on the answer https://stackoverflow.com/a/77864854/ provided by the user 'tomas' ( https://stackoverflow.com/u/992470/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: oracle.net.keepAlive vs connection pooling (Hikari CP/UCP pool idle connection timeout)

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding oracle.net.keepAlive in Connection Pooling: Hikari CP vs Oracle UCP

When working with databases in Java applications, managing connections efficiently is crucial for maintaining performance and reliability. Two popular solutions for connection pooling are Hikari CP and Oracle's Universal Connection Pool (UCP). Both offer various features that optimize database connections, but when it comes to handling idle connections, especially with TCP keepalive settings, many developers find themselves with questions. One common inquiry is about the behavior of connection pools concerning the oracle.net.keepAlive setting and how it interacts with idle connection timeouts.

The Challenge of Idle Connections

Idle connections can become an issue when applications do not efficiently manage database connections, leading to unnecessary resource consumption and potential timeouts.

Idle Timeout: When a connection sits idle for too long, it might be closed by the DB or the network, resulting in exceptions such as SQLRecoverableException: Closed Connection.

Keepalive Settings: Enabling TCP keepalives ensures that idle connections remain "alive" by periodically sending packets. However, there are nuances to consider when using different connection pooling libraries.

Hikari CP vs Oracle UCP Connection Pooling

Hikari CP

HikariCP is known for its performance and configuration options, particularly concerning idle connections.

Keepalive Configuration: You can set keepaliveTime in HikariCP, combined with a long idle timeout and maximum lifetime. This helps to prevent the premature closure of idle connections by firewalls.

Benefits: By managing idle connections effectively, Hikari allows applications to maintain operational efficiency and minimize connection-related errors.

Oracle UCP

Oracle UCP, while also powerful, presents its own set of challenges.

Lack of Keepalive Options: Unlike Hikari, UCP does not natively support a keepalive configuration. Therefore, developers must look for solutions on the JDBC driver level.

JDBC Driver Level Options: To enable keepalive at the JDBC driver, you can use settings like:

oracle.net.keepAlive

oracle.net.TCP_KEEPIDLE

oracle.net.TCP_KEEPINTERVAL

oracle.net.TCP_KEEPCOUNT

Impact of Enabling Keepalive on JDBC Driver

A question often arises: if keepalive is enabled at the JDBC driver level, how does this impact the connection pool's idleTimeout, especially when the pool size exceeds the minimumIdle?

Key Consideration

Connections Marked as Idle: If you enable keepalive at the JDBC level, connections will still be considered idle by the connection pool's management unless they are actively validated.

The keepalive packets will keep the TCP connection open; however, the connection pool will still drop it if it exceeds the configured idleTimeout, thus not considering it "alive" from a connection pool perspective.

Suggested Configuration for UCP

To address this issue in UCP, it's beneficial to manage connection validation explicitly:

Set validateConnectionOnBorrow=true: This ensures that a connection is checked for validity every time it is borrowed from the pool.

Adjust secondsToTrustIdleConnection=1800: This setting permits a 30-minute grace period for idle connections, allowing it to detect broken connections effectively.

With these settings, even without keepalive support, broken connections can still be identified and handled.

Conclusion

In summary, while both HikariCP and Oracle UCP have their methods for managing idle connections, understanding the nuances of oracle.net.keepAlive can significantly impact how your application handles database connections. By configuring appropr