Optimizer Feature Comparison Matrix

The below is a table view. For a more graphical view of the differences see What is the difference between MySQL and MariaDB query optimizers.

Feature	MariaDB 5.3/5.5	MariaDB 10.0	MySQL 5.5	MySQL 5.6
Disk access optimizations
Index Condition Pushdown (ICP)	YES	YES	-	YES
Disk-sweep Multi-range read (DS-MRR)	YES	YES	-	YES
DS-MRR with Key-ordered retrieval	YES	YES	-	-
Index_merge / Sort_intersection	YES	YES	-	-
Cost-based choice of range vs. index_merge	YES	YES	-	-
ORDER BY ... LIMIT <small_limit>	-	YES	-	YES
Use extended (hidden) primary keys for innodb/xtradb	YES (5.5)	YES	-	-
Join optimizations
Batched key access (BKA)	YES	YES	-	YES
Block hash join	YES	YES	-	-
User-set memory limits on all join buffers	YES	YES	-	-
Apply early outer table ON conditions	YES	YES	-	-
Null-rejecting conditions tested early for NULLs	YES	YES	-	-
Subquery optimizations
In-to-exists	YES	YES	YES	YES
Semi-join	YES	YES	-	YES
Materialization	YES	YES	-	YES
NULL-aware Materialization	YES	YES	-	-
Cost choice of materialization vs. in-to-exists	YES	YES	-	YES
Subquery cache	YES	YES	-	-
Fast explain with subqueries	YES	YES	-	-
EXISTS-to-IN	-	YES	-	-
Optimization for derived tables / views
Delayed materialization of derived tables / materialized views	YES	YES	-	YES
Instant EXPLAIN for derived tables	YES	YES	-	YES
Derived Table with Keys optimization	YES	YES	-	YES
Fields of merge-able views and derived tables used in equality optimizations	YES	YES	-	-
Execution control
LIMIT ROWS EXAMINED rows_limit	YES (5.5)	YES	-	-
Optimizer control (optimizer switch)
Systematic control of all optimizer strategies	YES	YES	-	partial
EXPLAIN improvements
Explain for DELETE, INSERT, REPLACE, and UPDATE	-	Partial	-	YES
EXPLAIN in JSON format	-	-	-	YES
More detailed and consistent EXPLAIN for subqueries	YES	YES	-	-
Optimizer trace
Optimizer trace	-	-	-	YES

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