[ethanseal]

I think having a way to build statistics on the join itself would be helpful for this. Similar to how extended statistics^1 can help when column distributions aren't independent of each other.

But this may require some basic materialized views, which postgres doesn't really have.

[1]: https://www.postgresql.org/docs/current/planner-stats.html#P...

[johnthescott]

could you elaborate on pg not really having matviews?

[ethanseal]

Materialized views in Postgres don't update incrementally as the data in the relevant tables updates.^1

In order to keep it up to date, the developer has to tell postgres to refresh the data and postgres will do all the work from scratch.

Incremental Materialized views are _hard_. This^2 article goes through how Materialize does it.

MSSQL does it really well from what I understand. They only have a few restrictions, though I've never used a MSSQL materialized view in production.^3

[1]: https://www.postgresql.org/docs/current/rules-materializedvi... [2]: https://www.scattered-thoughts.net/writing/materialize-decor... [3]: https://learn.microsoft.com/en-us/sql/t-sql/statements/creat...