Subquery Optimizations

Articles about subquery optimizations in MariaDB.

Title Description
Subquery Optimizations Map Map showing types of subqueries and the optimizer strategies available to handle them
Semi-join Subquery Optimizations MariaDB has a set of optimizations specifically targeted at semi-join subqueries
Table Pullout Optimization Table pullout is an optimization for Semi-join subqueries
Non-semi-join Subquery Optimizations Alternative strategies for IN-subqueries that cannot be flattened into semi-joins
Subquery Cache Subquery cache for optimizing the evaluation of correlated subqueries.
Condition Pushdown Into IN subqueries This article describes Condition Pushdown into IN subqueries as implemented...
Conversion of Big IN Predicates Into Subqueries The optimizer will convert big IN predicates into subqueries.
EXISTS-to-IN Optimization MariaDB 5.3 introduced a rich set of optimizations for IN subqueries
Optimizing GROUP BY and DISTINCT Clauses in Subqueries MariaDB removes DISTINCT and GROUP BY without HAVING in certain cases
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https://mariadb.com/kb/en/subquery-optimizations/