If you join multiple/many tables, you could end up with a large volume of data. And yes, this is bit-for-bit duplication—on the network. The query result is (typically) a single table. This table will get serialized as-is, with all duplicate data.

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exceptione 3 hours ago | parent [-]

Couldn't we make references as `byte offsets in the result set` work to handle duplication? Real memory pointers wouldn't work over the network of course, but if the database driver would return results like this, the client could easily stitch these together. My hunch is that even if we implement references on a higher level than raw byte offsets it would still be more performant than just returning R1*R2 bytes for any R1<1:N>R2.

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EDIT: According to LLM friends you could achieve before wire de-duplication by using FOR JSON AUTO in SQL Server or jsonb_agg in PostgreSQL. Not sure how much overhead that incurs though.

	▲	CodesInChaos an hour ago \| parent [-]
		You'd still return a multiplicative amount of rows, even if those rows contained only a reference. `array_agg` in postgres avoids this, but EF does not support using it for collection navigations. One could envision a "Cartesian product" operation in the wire protocol, but I'm not convinced that's a good approach.