Medallion architecture, how to update Gold tables?

[Mado]

Assume that I have a data source that is ingested to a few bronze tables, and transformed to a silver table. Ans next, a gold table is created by aggregating the silver table.

If new records arrive in the data source, bronze and silver tables are updated by appending new records. Since the gold table contains aggregated values, using "append" is meaningless.

I'd like to know which approach is recommended to update gold tables in case of having a large dataset:

1) Drop the current gold table, and re-create it

2) Overwrite the gold table

The first option seems to be slower if we deal with a large dataset. However, I'd like to know if there is any risk with option 2 (e.g. if the table is not overwritten correctly).

[daniel_sahal]

@Mohammad Saber​ 

Why not using MERGE? Or even CDF + Merge to do increments.

https://sarnendude.com/delta-lakes-change-data-feed-cdf-demo-in-azure-databricks/

[Mado]

When there is aggregated value in the Gold table, I think it should be calculated using all records in the Silver table.

[Anonymous]

Hi @Mohammad Saber​ 

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[Mado]

Hi @Vidula Khanna​ 

The answer didn't fit my question.

In the case of using Merge, I found a good article here:

https://medium.com/@avnishjain22/simplify-optimise-and-improve-your-data-pipelines-with-incremental-...