Query Optimizer

Delve into the MariaDB Server query optimizer. This section provides internal documentation on how queries are parsed, optimized, and executed for maximum efficiency and performance.

Block-Based Join Algorithms

Block-based join algorithms in MariaDB: Block Nested Loop, Block Hash Join, and Batch Key Access.

Condition Selectivity Computation Internals

How the optimizer computes condition selectivities (internals).

Extended Keys

The Extended Keys optimization, which uses primary-key parts appended to secondary indexes.

MIN/MAX optimization

The MIN/MAX optimization, which resolves MIN() and MAX() from an index without scanning rows.

Notes When an Index Cannot Be Used

Situations in which the optimizer cannot use an index.

Optimizer Debugging With GDB

Tips for debugging MariaDB optimizer code with GDB.

Optimizer Development

Notes on MariaDB optimizer development.

optimizer_max_sel_arg_weight

The optimizer_max_sel_arg_weight setting, which caps the complexity of range analysis.

Range Optimizer

The range optimizer, which builds range scans from WHERE conditions.

The Optimizer Cost Model from MariaDB 11.0

The optimizer cost model introduced in MariaDB 11.0.

Optimizer Trace

Optimizer trace, which records how the optimizer builds a query's execution plan.