🎳Impact Analysis

What will happen if I delete this table?

To understand the impact a change would have in your environment before executing it and risking breaking changes, you can test them in the Impact Analysis page.

How do I start?

You can visit it either from the main menu or directly from an Entity View.

Select sources

If it’s the former, start by choosing the source entities from the Select sources picklist.

Depending on your use case search for tables or single columns.

You can choose multiple sources, but your results will grow proportionately more complex. We recommend starting with one.

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Whenever applicable you can enter Impact Analysis directly from the Table and Column Details views, so you don't have to search for your source entity.

Select entity types

Secondly, you need to choose the entity types you want to be considered in the analysis.

The default selection is Tables and Dashboards, which are the most significant. For more granular results you can add Explores and Looks. Including more entity types can make the result set much larger and potentially harder to investigate, so we recommend keeping it to the minimum required for your use case.

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The entity types not chosen in this filter will be skipped in the lineage traversal, but entities of the selected type downstream from those will still appear.

Practical example

You chose to only include tables and dashboards, but not explores. The analysis will go via explores and include the dashboards downstream, but the report will not show the explores themselves.

The Report

The results will show every asset that would be affected by changing or deleting your source entity. It stays the same for every type of change considered in Depth of lineage. On the top you will see the count of affected Dashboards, Tables and Columns, as well as the number of queries ran against them in the last 30 days.

Alvin sorts the results starting from highest usage in a tree structure. You can filter out the entities with or without analytical usage, or search in the names.

The underlying graph can be visualised in three different ways.

Visualise

By Source

Visualise the impact going downstream step by step in a tree structure.

By Destination

See the furthest reaching impacts of the change, and trace to the source backwards (upstream).

Links

See the summary of all connections. Sort by distance to or analytical usage of the impact's end-point.

Expand and collapse the lineage with Hide/Show N down-/upstream, and understand the connections with View Link Details.

Analyse Connection Details

The Link Details page will show you details on how the entities are connected. Depending on the type of connection, you will see one of the two tabs.

Overview of all the related jobs and models.

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A lineage graph.

Sharing the results

You can share the results with your teammates or save them for later simply by copying the URL from your browser.

The results don't change dynamically with your schema between syncs. Check top right of the page to see the connection details and to make sure which sync they're applicable to.