optimizer_switch
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Contents
optimizer_switch is a server variable that one can use to enable/disable specific optimizations. For generic syntax, see Switchable Optimizations in MySQL Manual.
Available flags
Below is a list of all @@optimizer_switch flags available in MariaDB:
Defaults
| From version | Default optimizer_switch setting |
|---|---|
| MariaDB 10.3.0 | index_merge=on, index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on, index_merge_sort_intersection=off, engine_condition_pushdown=off, index_condition_pushdown=on, derived_merge=on, derived_with_keys=on, firstmatch=on, loosescan=on, materialization=on, in_to_exists=on, semijoin=on, partial_match_rowid_merge=on, partial_match_table_scan=on, subquery_cache=on, mrr=off, mrr_cost_based=off, mrr_sort_keys=off, outer_join_with_cache=on, semijoin_with_cache=on, join_cache_incremental=on, join_cache_hashed=on, join_cache_bka=on, optimize_join_buffer_size=off, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on |
| MariaDB 10.2.6 | index_merge=on, index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on, index_merge_sort_intersection=off, engine_condition_pushdown=off, index_condition_pushdown=on, derived_merge=on, derived_with_keys=on, firstmatch=on, loosescan=on, materialization=on, in_to_exists=on, semijoin=on, partial_match_rowid_merge=on, partial_match_table_scan=on, subquery_cache=on, mrr=off, mrr_cost_based=off, mrr_sort_keys=off, outer_join_with_cache=on, semijoin_with_cache=on, join_cache_incremental=on, join_cache_hashed=on, join_cache_bka=on, optimize_join_buffer_size=off, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on |
| MariaDB 10.1.15 | index_merge=on, index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on, index_merge_sort_intersection=off, engine_condition_pushdown=off, index_condition_pushdown=on, derived_merge=on, derived_with_keys=on, firstmatch=on, loosescan=on, materialization=on, in_to_exists=on, semijoin=on, partial_match_rowid_merge=on, partial_match_table_scan=on, subquery_cache=on, mrr=off, mrr_cost_based=off, mrr_sort_keys=off, outer_join_with_cache=on, semijoin_with_cache=on, join_cache_incremental=on, join_cache_hashed=on, join_cache_bka=on, optimize_join_buffer_size=off, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=off |
| MariaDB 10.1.0 | index_merge=on, index_merge_union=on, index_merge_sort_union=on, index_merge_intersection=on, index_merge_sort_intersection=off, engine_condition_pushdown=off, index_condition_pushdown=on, derived_merge=on, derived_with_keys=on, firstmatch=on, loosescan=on, materialization=on, in_to_exists=on, semijoin=on, partial_match_rowid_merge=on, partial_match_table_scan=on, subquery_cache=on, mrr=off, mrr_cost_based=off, mrr_sort_keys=off, outer_join_with_cache=on, semijoin_with_cache=on, join_cache_incremental=on, join_cache_hashed=on, join_cache_bka=on, optimize_join_buffer_size=off, table_elimination=on, extended_keys=on, exists_to_in=on |
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