The Schema tab allows you to select whether nested JSON automatically unpacks, and lists the Dataset’s Unique Fields and Derived Columns.
Unique Fields lists all the unique fields seen in events from this dataset. You can modify a field’s data type here if needed.
0) rather than dropping the value. Each Dataset allows you to define unique custom fields for use within it.
Otherwise known as Derived Columns, custom fields are computed properties that are calculated by a formula.
The field’s value is based on the result of a formula, which can contain functions, mathematical and/or logical operations on other field values, and constants and literals, similar to expressions defined in a spreadsheet. To learn more about syntax and available functions, visit Derived Column Formula Reference.
Though functionally different, you can use custom fields in Honeycomb just as you would use other fields in your data (building queries; defining Triggers and Service Level Objectives (SLOs)). For example, you can use custom fields to express:
Some examples include:
Example scenario:
Your team manages a web server that handles requests with varying sizes of content.
Querying with GROUP BY content_length returns a time series graph that displays the count for each value of content_length.
You want to compare small requests to all other requests.
Your team internally categorizes a small request as having a content_length of less than or equal to 1000.
Solution:
Create a Derived Column named smallRequest with the function LTE($content_length, 1000).
When you query in Honeycomb with a GROUP BY clause of smallRequest, you receive a time series graph that displays the small requests alongside the other requests.
Example scenario: Your team has an Environment named “Production”, which contains Datasets named “PaymentService”, “CheckoutService”, and “SupportService”. You have defined a derived column with the same name in each Dataset:
| Dataset | Derived Column Name | Formula |
|---|---|---|
| PaymentService | total_amount_in_usd | COALESCE($usd_total, ADD(MUL($tax_rate, $item_total), $fees)) |
| CheckoutService | total_amount_in_usd | MUL($cart_total, $tax_rate) |
| SupportService | total_amount_in_usd | SUM(0) |
When you query across the Production Environment in Honeycomb, you receive:
total_amount_in_usd values calculated with its expressiontotal_amount_in_usd values calculated with its expressiontotal_amount_in_usd values calculated with its expressionYou cannot define an Environment-level Derived Column for “Production” with the name total_amount_in_usd because the name is already used by a Dataset-level Derived Column in one or more datasets.
Solution: Name the Environment-level Derived Column something unique to your Environment or change your instrumentation to rename the Derived Columns in the Datasets.
To create a Derived Column:
Log in to the Honeycomb UI.
Select the Environments label on the top-left, then select the Environment that contains the Dataset to which you would like to add a Derived Column.
In the left navigation menu, select Manage Data.
In the list, locate and select Datasets.
In the list, locate the Dataset to which you would like to add a Derived Column, and select its name to view the available settings.
Navigate to the Schema view.
Select Add new Derived Column.
In the modal, enter a Display Name, which will show as the field name in the Query Builder.
Enter a display name that is unique across the Dataset and its containing Environment. Your Derived Column name should not match the name of any other Derived Column or any other field in any Dataset contained within the Environment.
Although Honeycomb tries to prevent duplicate field names, they can still occur. To learn more about behaviors related to name collision and solutions, visit Common Issues with Queries: Derived Columns.
In the editor, define the formula for your Derived Column. To learn more about syntax and available functions, and to explore some example formulas, visit Derived Column Formula Reference.
Hover over any syntax errors (red underlines or red triangles) for assistance with correcting them.
Select Save.
To change a Derived Column:
Log in to the Honeycomb UI.
Select the Environments label on the top-left, then select the Environment that contains the Dataset for which you would like to change a Derived Column.
In the left navigation menu, select Manage Data.
In the list, locate and select Datasets.
In the list, locate the Dataset for which you would like to change a Derived Colum, and select its name to view the available settings.
Navigate to the Define Schema view.
In the list, locate the Derived Column that you want to edit, and select Edit.
If any dependencies exist, Honeycomb will prompt you to choose whether to clone or continue editing the Derived Column. If you are unsure about whether to clone or edit, reach out to the Derived Column’s most recent editor.
In the modal, modify the pre-populated name and formula as needed. To learn more about syntax and available functions, and to explore some example formulas, visit Derived Column Formula Reference.
Select Save.
If you have a Derived Column that is similar to one you want to create, you can clone it and use it as the base for a new Derived Column. To clone a Derived Column:
Log in to the Honeycomb UI.
Select the Environments label on the top-left, then select the Environment that contains the Dataset for which you would like to clone a Derived Column.
In the left navigation menu, select Manage Data.
In the list, locate and select Datasets.
In the list, locate the Dataset that contains the Derived Column you want to clone, and select its name to view the available settings.
Navigate to the Define Schema view.
In the list, locate the Derived Column that you want to clone, and select Clone.
In the modal, modify the pre-populated name and formula as needed. To learn more about syntax and available functions, and to explore some example formulas, visit Derived Column Formula Reference.
Select Save.
Deleting a Derived Column may affect Boards, Triggers, or SLOs.
Only the derived column’s creator or a Team Owner can delete a derived column in the Honeycomb UI.
Log in to the Honeycomb UI.
Select the Environments label on the top-left, then select the Environment that contains the Dataset for which you want to delete a Derived Column.
In the left navigation menu, select Manage Data.
In the list, locate and select Datasets.
In the list, locate the Dataset that contains the Derived Column you want to delete, and select its name to view the available settings.
Navigate to the Define Schema view.
In the list, locate the Derived Column that you want to delete, and select Delete.
If any dependencies exist, you will see a list of dependencies that you must remove to continue. If you are unsure about whether to remove the dependencies, reach out to each dependency’s most recent editor. After removing all dependencies, select Refresh Dependencies.
From the modal, select Delete.
Queries that use your Derived Column will continue to work, but the alias will no longer appear in the Query Builder.