> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies.md).

# Optimization Strategies

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[Duplicate Weedout Strategy](/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies/duplicateweedout-strategy.md)
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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.
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[FirstMatch Strategy](/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies/firstmatch-strategy.md)
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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.
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[Improvements to ORDER BY Optimization](/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies/improvements-to-order-by.md)
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Describes MariaDB improvements to the ORDER BY optimizer, including cost- based index switching for ORDER BY with small LIMIT and multiple-equality handling.
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[LooseScan Strategy](/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies/loosescan-strategy.md)
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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.
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[Semi-join Materialization Strategy](/docs/server/ha-and-performance/optimization-and-tuning/query-optimizations/optimization-strategies/semi-join-materialization-strategy.md)
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Semi-join Materialization runs an uncorrelated IN-subquery into a temporary table, then joins it via the Materialization-scan or Materialization-lookup strategy.
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