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Are the pushdown problems you're experiencing with postgres, or something else? If with PG, I'd very much welcome you to report them. While we know about some w

• thom 9y ago
  Yeah, I'm not really proposing some specialised ML algorithm within Postgres to handle these edge cases, I'm more hoping that someone comes along with an entirely new paradigm for describing data and queries, that allows a platform to evolve on top of that for maximum performance given the described workload. In a particular case that annoyed me this week, casting an IN clause with a subquery to an array (on a query over a view with a GROUP BY) resulted in wildly better performance, despite setting the statistics target to the maximum value, indexing everything etc. I'm happy to demonstrate a trivial reproduction of this issue, and I'm sure I'm a crap DBA, but every day it's the same fight - SQL is _not_ a declarative language. It is incredibly sensitive to implementation details, in ways that are way less obvious than any other programming language. Postgres could do a better job in all sorts of situations, but I personally think that finding all these edge cases algorithmically or analytically is futile. A platform built on a paradigm more closely aligned to the logical descriptions of data and queries could, over time, learn to perform better.