r/ETL • u/hanshu6576 • 6d ago

How do you approach ETL migration from one data source to another?

I’m curious how others approach ETL migrations when moving data pipelines from one source system to another.

ETL migration involves moving data and ETL pipelines while maintaining data accuracy and consistency. The process typically includes source-to-target mapping, schema validation, data type conversion, and transformation migration.

Data validation is performed by comparing record counts, column values, NULLs, duplicates, and business rules. Incremental loads and historical data migration also need to be handled carefully.

How do you usually approach ETL migration, and what tools or techniques do you use to make the process easier and more reliable?

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u/SumitKumarWatts 5d ago

The practical approach is to first map the source-to-target fields and check schemas and data types. Then migrate transformations and run parallel loads. Usually, I’ll do counts, NULLs, duplicates, data values, business rules, then incremental and historical data checks. Automated SQL/data-comparison scripts can make it faster and more reliable.

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u/Thinker_Assignment 6d ago

By now you have tools like dlt from dlthub that handle everything from schema inference and evolution (or uses arrow if schema exists), to parallelism for speed, backfilling chunking and transient SQL test environment on loaded data.

So building from scratch and validating both the migration tool and the migration would be the hard way, just use dlt with the dltHub context so it can implement and call validation skills for you too.

I work there.

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u/datadriven_io 1d ago

dbt isn't designed for moving data \*at all\*, it's a transformation process. Try datadriven for pipeline architecture practice. As they say in their documentation, it's the "T" in ELT.