Скачать или смотреть Solving the Critical System Error in Apache Ignite with WAL Disabled

Discover effective solutions for managing `Apache Ignite` errors related to native persistence and disabled WAL logging, helping ensure smooth server restarts.
---
This video is based on the question https://stackoverflow.com/q/66686985/ asked by the user 'Henrik' ( https://stackoverflow.com/u/844828/ ) and on the answer https://stackoverflow.com/a/66688052/ provided by the user 'alamar' ( https://stackoverflow.com/u/36498/ ) 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: Apache Ignite: Reached logical end of the segment for file

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.
---
Tackling the Critical System Error in Apache Ignite

If you're working with Apache Ignite and have enabled native persistence while disabling the Write-Ahead Log (WAL), you might encounter a perplexing problem when trying to restart your server. This often manifests as a critical system error. Understanding how to address this issue is crucial for efficient database management and server operations.

The Problem at Hand: Log Errors After Server Shutdown

When you run an Ignite server with these configurations:

[[See Video to Reveal this Text or Code Snippet]]

You might experience the following error after stopping the server:

[[See Video to Reveal this Text or Code Snippet]]

In addition, you might see messages indicating a logical end of a segment for a WAL file. This can happen due to the way the server is shut down or the configuration settings you've employed.

Understanding the Solution

To resolve this issue, follow these recommended steps:

1. Avoid Using walMode=NONE

Using the walMode=NONE setting can lead to complications like those you're experiencing. It’s advisable to reconsider this configuration unless absolutely necessary. If you must keep this setting, you should:

Purge the Persistence Directory: Before restarting your Ignite node, ensure you delete the entire persistence directory to clear any existing state. This includes the WAL files that may still be lingering.

2. Proper Server Shutdown

To avoid abrupt errors when shutting down the server:

Set the Cluster State to INACTIVE: Before stopping your Ignite nodes, invoke the following command in your code:

[[See Video to Reveal this Text or Code Snippet]]

This command ensures that the cluster is properly deactivated, potentially preventing issues related to checkpoint reads.

3. General Best Practices

Here are more best practices you should consider when working with Apache Ignite:

Regular Backups: Always back up your data before making significant configuration changes. This can save you from potential data loss.

Monitor Logs: Keep an eye on both application logs and Ignite's specific logs to detect any signs of issues early.

Use Configuration Templates: Maintain a few standard configuration files tailored for specific use cases to streamline your setup process.

Conclusion

Dealing with Apache Ignite can sometimes lead to nuances such as the critical errors encountered when both native persistence is enabled and WAL is disabled. By re-evaluating your WAL settings, properly managing server shutdowns, and following best practices, you can ensure a smoother experience with Ignite.

Implement these steps, and you'll be better equipped to manage your Ignite server and avoid unexpected issues.