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Visualizing a SQL query in 5 mins SQL statements are executed by the database system in several steps, including: - Parsing the SQL statement and checking its validity - Transforming the SQL into an internal representation, such as relational algebra - Optimizing the internal representation and creating an execution... show more
23,200 görüntüleme • 1 ay önce •via X (Twitter)
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@bytebytego @sahnlam I always find it eye-opening to peek at actual execution plans in the database console. That moment when you spot an unexpected table scan is humbling. 💪

@bytebytego @sahnlam the hard part is understanding which optimization to choose, not just transforming sql into algebra, that's a solved problem

@bytebytego @sahnlam Also, "Predicate Pushdown" can allow filtering and removal of rows prior to a join. All records are not always joined/merged prior to filtering.

@bytebytego @sahnlam EXPLAIN ANALYZE remata bien ese recorrido: enseña filas y tiempos reales de cada paso, no solo el plan estimado.

@bytebytego @sahnlam Btw, great overview.

@bytebytego @sahnlam Thanks for sharing this wonderful insight Very helpful

@bytebytego @sahnlam Execution plan also considers histogram statistics to determine and use more efficient execution plans. An example is to skip using an index when a full tab scan would be less costly.

