How To Optimize Iceberg Tables in AWS Glue Using Table Optimization

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If you’re working with Apache Iceberg tables in AWS Glue and notice that your table optimizations aren’t showing any visible changes in your S3 bucket, don’t worry. Here’s a simple step-by-step guide to help you troubleshoot and resolve the issue.

First, make sure that table optimization features are turned on. You can do this by going to the AWS Glue console and checking the “Table optimization” section for your specific table. It’s important to confirm that the optimization is enabled correctly.

Next, check the optimizer’s history to see if it has successfully run. In the same console section, select “View optimization history” to see past optimization jobs. If recent runs are missing, the optimizer may not be functioning properly.

Also, ensure that the IAM role associated with AWS Glue has the right permissions to access and make changes to your S3 storage. Without proper permissions, the optimizer can’t execute its tasks.

If your setup uses a Virtual Private Cloud (VPC), double-check that the optimizer is configured with the correct network connection so it can operate within your VPC environment smoothly.

Another key point is that default settings for new tables often have optimization features like compaction turned off. You will need to modify these settings manually via the console, Command Line Interface (CLI), or API to activate them.

Keep in mind, if you’ve set optimization options at both the catalog and table levels, the table-specific settings will override the catalog defaults. Confirm that the settings you want are active on the particular table.

When it comes to compaction, check if you’ve chosen a strategy—such as binpack, sort, or Z-order. Binpack is the default, and it works by merging small files into larger ones, which helps improve performance.

Finally, remember that table optimizations don’t happen instantly. It can take some time for the process to complete and for changes to appear in your S3 bucket. Patience is key: wait for the scheduled or manual optimization to finish before expecting to see updated files.

By following these steps, you should be able to resolve why you’re not seeing updates and ensure your Iceberg tables are optimized efficiently.