Working with Machine Learning Transforms on the AWS Glue Console

You can use AWS Glue to create custom machine learning transforms that can be used to cleanse your data. You can use these transforms when you create a job on the AWS Glue console.

For information about how to create a machine learning transform, see Matching Records with AWS Lake Formation FindMatches.

Transform Properties

To view an existing machine learning transform, sign in to the AWS Management Console, and open the AWS Glue console at https://console.aws.amazon.com/glue/. Then choose the ML transforms tab.

The Machine Learning Transforms list displays the following properties for each transform:

Transform name

The unique name you gave the transform when you created it.

Transform ID

A unique identifier of the transform.

Type

The type of machine learning transform; for example, Find matching records.

Glue version

This value determines which version of AWS Glue this machine learning transform is compatible with. Glue 1.0 is recommended for most customers. If the value is not set, the Glue compatibility defaults to Glue 0.9. For more information, see AWS Glue Versions.

Status

Indicates whether the transform is Ready or Needs teaching. To run a machine learning transform successfully in a job, it must be Ready.

When you create a FindMatches transform, you specify the following configuration information:

Primary key

The name of a column that uniquely identifies rows in the source table.

Type

The type of machine learning transform; for example, Find matches.

Merge matching records

Indicates whether the transform is to remove duplicates in the target. The record with the lowest primary key value is written to the output of the transform.

Adding and Editing Machine Learning Transforms

You can view, delete, set up and teach, or tune a transform on the AWS Glue console. Select the check box next to the transform in the list, choose Action, and then choose the action that you want to take.

To add a new machine learning transform, choose the Jobs tab, and then choose Add job. Follow the instructions in the Add job wizard to add a job with a machine learning transform such as FindMatches. For more information, see Matching Records with AWS Lake Formation FindMatches.

Viewing Transform Details

Transform details include the information that you defined when you created the transform. To view the details of a transform, select the transform in the Machine learning transforms list, and review the information on the following tabs:

• History

• Details

• Estimate quality

History

The History tab shows your transform task run history. Several types of tasks are run to teach a transform. For each task, the run metrics include the following:

• Run ID is an identifier created by AWS Glue for each run of this task.

• Task type shows the type of task run.

• Status shows the success of each task listed with the most recent run at the top.

• Error shows the details of an error message if the run was not successful.

• Start time shows the date and time (local time) that the task started.

• Execution time shows the length of time during which the job run consumed resources. The amount is calculated from when the job run starts consuming resources until it finishes.

• Last modified shows the date and time (local time) that the task was last modified.

• Logs links to the logs written to stdout for this job run.

  The Logs link takes you to Amazon CloudWatch Logs. There you can view the details about the tables that were created in the AWS Glue Data Catalog and any errors that were encountered. You can manage your log retention period on the CloudWatch console. The default log retention is Never Expire. For more information about how to change the retention period, see Change Log Data Retention in CloudWatch Logs in the Amazon CloudWatch Logs User Guide.

• Error logs links to the logs written to stderr for this task run.

  This link takes you to CloudWatch Logs, where you can see details about any errors that were encountered. You can manage your log retention period on the CloudWatch console. The default log retention is Never Expire. For more information about how to change the retention period, see Change Log Data Retention in CloudWatch Logs in the Amazon CloudWatch Logs User Guide.

• Download label file shows a link to Amazon S3 for a generated labeling file.

Details

The Details tab includes attributes of your transform. It shows you the details about the transform definition, including the following:

• Transform name shows the name of the transform.

• Type lists the type of the transform.

• Status displays whether the transform is ready to be used in a script or job.

• Force output to match labels displays whether the transform forces the output to match the labels provided by the user.

Estimate quality

The Estimate quality tab shows the metrics that you use to measure the quality of the transform. Estimates are calculated by comparing the transform match predictions using a subset of your labeled data against the labels you have provided. These estimates are approximate.You can invoke an Estimate quality task run from this tab.

The Estimate quality tab shows the metrics from the last Estimate quality run including the following properties:

• Area under the Precision-Recall curve is a single number estimating the upper bound of the overall quality of the transform. It is independent of the choice made for the precision-recall parameter. Higher values indicate that you have a more attractive precision-recall tradeoff.

• Precision estimates how often the transform is correct when it predicts a match.

• Recall upper limit estimates that for an actual match, how often the transform predicts the match.

• Max F1 estimates the transform's accuracy between 0 and 1, where 1 is the best accuracy. For more information, see F1 score in Wikipedia.

For information about understanding quality estimates versus true quality, see Quality Estimates Versus End-to-End (True) Quality.

For more information about tuning your transform, see Tuning Machine Learning Transforms in AWS Glue.

Quality Estimates Versus End-to-End (True) Quality

In the FindMatches machine learning transform, AWS Glue estimates the quality of your transform by presenting the internal machine-learned model with a number of pairs of records that you provided matching labels for but that the model has not seen before. These quality estimates are a function of the quality of the machine-learned model (which is influenced by the number of records that you label to “teach” the transform). The end-to-end, or true recall (which is not automatically calculated by the FindMatches transform) is also influenced by the FindMatches filtering mechanism that proposes a wide variety of possible matches to the machine-learned model.

You can tune this filtering method primarily by using the Lower Cost-Accuracy slider. As you move this slider closer to the Accuracy end, the system does a more thorough and expensive search for pairs of records that might be matches. More pairs of records are fed to your machine-learned model, and your FindMatches transform's end-to-end or true recall gets closer to the estimated recall metric. As a result, changes in the end-to-end quality of your matches as a result of changes in your matches's cost/accuracy tradeoff will typically not be reflected in the quality estimate.