Every time I demo Snowflake to someone new, zero-copy cloning gets the biggest reaction. You type one line. You get an instant copy of a table — or an entire database — with no data duplication, no storage cost at the moment of creation. It feels like magic.
And it is genuinely impressive engineering. I’m not here to tell you it’s a bad feature. It’s one of my favourite things about Snowflake and I use it constantly.
But I’ve watched teams get badly surprised by it. A dev environment clone that started silently inflating the storage bill. A cloned database used for UAT that bypassed data masking policies on PII columns. A Time Travel query on a clone that returned nothing because the source table’s retention window had already expired.
None of these are edge cases. They’re predictable consequences of how zero-copy cloning actually works — consequences that the marketing language around “instant, free copies” tends to obscure. Let me get into it.
