Optimization Strategies

Discover effective optimization strategies for MariaDB Server queries. This section provides a variety of techniques and approaches to enhance query performance and overall database efficiency.

Duplicate Weedout Strategy

DuplicateWeedout is a semi-join execution strategy that runs the subquery as a regular inner join and removes duplicate record combinations using a temporary table.

FirstMatch Strategy

FirstMatch is a semi-join execution strategy that avoids duplicate results by short-cutting subquery execution as soon as the first matching record is found, improving performance.

Improvements to ORDER BY Optimization

Describes MariaDB improvements to the ORDER BY optimizer, including cost- based index switching for ORDER BY with small LIMIT and multiple-equality handling.

LooseScan Strategy

LooseScan is a semi-join execution strategy that avoids duplicate record combinations by using an index on the subquery table to pick one row per group.

Semi-join Materialization Strategy

Semi-join Materialization runs an uncorrelated IN-subquery into a temporary table, then joins it via the Materialization-scan or Materialization-lookup strategy.