I've been writing on an extensive ELT 101 - Why and What
, because I couldn't find a good one out there (no Meltano ads inside, just plain old content) https://meltano.com/blog/elt-101-the-why-and-what-of-elt-or-the-why-not-of-etl/
• ETL was super helpful a decade ago!
• But the assumptions that made ELT super useful don't hold any more (expensive storage, limited compute abilities of databases)
• Now the world is cluttered with lots of ETL marketing, making it hard to see what's really going on.
• ELT should be the default choice, always (and the rise of dbt backs that up).
• Companies still on ETL should consider a switch.
• ELT and ETL are architecture patterns for data pipelines. ETL is usually implemented with one ETL or data integration tool; ELT is usually implemented with one EL and one T tool (e.g., dbt).
• Beware of the words "ETL tool" or "ELT" tools. There aren't any good conventions yet on those. (While there are ETL tools that support the ETL pattern, ELT usually is built with at least two tools. So an ELT tool is either a T only or an EL only tool - more confusion!)