I finally found out why the old "about" post said "Optimize it yourself".



  • I didn't actually think Oracle would be so stupid, until last friday. One of our customers had been complaining about agonizing slowness of some queries. When we finally managed to make EXPLAIN PLAN work in SQL Developer, it turned out Oracle, in its infinite wisdom, had decided it was a good idea to join a 66M rows table and a 650K rows table with nested loops. We had to use that weirdly-comment-like-but-not-actually "hint" syntax to tell it to use a more reasonable hash-join.



  • @Medinoc Or refresh your statistics, I believe. But hints tend to be more reliable.

    I get the impression one of the problems is it doesn't back out of a plan when it clearly should (like when finding out during execution that a certain subquery has 10M+ rows instead of 15).



  • @Medinoc said in I finally found out why the old "about" post said "Optimize it yourself".:

    I didn't actually think Oracle would be so stupid, until last friday. One of our customers had been complaining about agonizing slowness of some queries. When we finally managed to make EXPLAIN PLAN work in SQL Developer, it turned out Oracle, in its infinite wisdom, had decided it was a good idea to join a 66M rows table and a 650K rows table with nested loops. We had to use that weirdly-comment-like-but-not-actually "hint" syntax to tell it to use a more reasonable hash-join.

    If you had purchased an Oracle Certified Optimization Consultant Kit for $5000 + $500/hour, you wouldn't have these problems.


  • Impossible Mission Players - A

    @Dragnslcr said in I finally found out why the old "about" post said "Optimize it yourself".:

    If you had purchasedconsented to being sodomized by an Oracle Certified Optimization Consultant Kit for $5000 + $500/hour, you wouldn't have these problems.

    FTFY 🚎


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