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Training a 4B model to produce 81% faster query plans than Postgres

702 points · 144 comments · polyphilz

  1. hamilyon2 · · focus · HN ↗
    Optimal plan construction is math-heavy, algorithm-heavy and vary even by workload. There are options like creating just-in-time indexes, so solution space grows even faster than article presents. Sometimes it is the query planner which is the slow part of total execution time.

    LLM is kind of blunt weapon to use here. I am waiting rather for alphago style neural net heuristic.

    1. yipinwong · · focus · HN ↗
      What if we use a hybrid model of using both query optimizer and LLM? Whichever produces better result, the database can use?

      - a question from someone with lack of DB depth, me.

      1. Sesse__ · · focus · HN ↗
        The immediate problem: How do you know which one is better without running them?
        1. haroldl · · focus · HN ↗
          You create formulas to estimate the cost of running a given query plan. Use statistics collected about the tables (e.g. how many rows) to try to be accurate. The topic is "Cost Based Optimization".
          1. Sesse__ · · focus · HN ↗
            If you have formulas that actually match reality, what do you need the LLM for? An optimizer is perfectly capable of finding the optimal plan if it has a perfect estimator. In fact, if you could only estimate the number of rows in each subplan perfectly, you have as good as solved the problem already.
            1. pbalau · · focus · HN ↗
              > If you have formulas that actually match reality, what do you need the LLM for?

              Because one could be in that state where they are trying to use a tech they know preciously little about to solve a problem they know nothing about.

              This reminds me of a request we got from our "AI Department": if you build us a proper shares market simulator, we will build you an awesome agent that can trade shares. They seemed quite confused when I pointed out that if we could build such a simulator, we wouldn't need them anymore.

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