optimizer_switch
optimizer_switch — это переменная сервера, которую можно использовать для включения/выключения определённых оптимизаций.
Синтаксис
Для установки или отключения различных оптимизаций используйте следующий синтаксис:
SET [GLOBAL|SESSION] optimizer_switch='cmd[,cmd]...';
cmd имеет следующий формат:
| Синтаксис | Описание |
|---|---|
| default | Сбросить все оптимизации до их значений по умолчанию. |
| optimization_name=default | Установить указанную оптимизацию в её значение по умолчанию. |
| optimization_name=on | Включить указанную оптимизацию. |
| optimization_name=off | Отключить указанную оптимизацию. |
Нет необходимости перечислять все флаги — будут затронуты только те, которые указаны в команде.
Доступные флаги
Ниже приведен список всех флагов optimizer_switch, доступных в MariaDB:
- ↑ заменено на split_grouping_derived, введено в MariaDB 10.3.1
Значения по умолчанию
| С версии | Настройка optimizer_switch по умолчанию |
|---|---|
| MariaDB 11.0.2 | 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=on, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on, split_materialized=on, condition_pushdown_for_subquery=on, rowid_filter=on,condition_pushdown_from_having=on, not_null_range_scan=off, hash_join_cardinality=on |
| MariaDB 10.6.13, MariaDB 10.11.3 | 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=on, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on, split_materialized=on, condition_pushdown_for_subquery=on, rowid_filter=on,condition_pushdown_from_having=on, not_null_range_scan=off, hash_join_cardinality=off |
| MariaDB 10.5.0 | 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=on, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on, split_materialized=on, condition_pushdown_for_subquery=on, rowid_filter=on,condition_pushdown_from_having=on, not_null_range_scan=off |
| MariaDB 10.4.3 | 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=on, table_elimination=on, extended_keys=on, exists_to_in=on, orderby_uses_equalities=on, condition_pushdown_for_derived=on, split_materialized=on, condition_pushdown_for_subquery=on, rowid_filter=on,condition_pushdown_from_having=on |
| MariaDB 10.4.0 | 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, split_materialized=on, condition_pushdown_for_subquery=on |
| MariaDB 10.3.4 | 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, split_materialized=on |
| MariaDB 10.2.2 | 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 10.0.12 | 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 |
| MariaDB 10.0.9 | 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=off |
| MariaDB 10.0.2 | 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=off, exists_to_in=off |
| MariaDB 5.5.21 | 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=off |
| MariaDB 5.5.20 | 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 |
| MariaDB 5.3.3 | index_merge=вкл., index_merge_union=вкл., index_merge_sort_union=вкл., index_merge_intersection=вкл., index_merge_sort_intersection=выкл., index_condition_pushdown=вкл., derived_merge=вкл., derived_with_keys=вкл., firstmatch=вкл., loosescan=вкл., materialization=вкл., in_to_exists=вкл., semijoin=вкл., partial_match_rowid_merge=вкл., partial_match_table_scan=вкл., subquery_cache=вкл., mrr=выкл., mrr_cost_based=выкл., mrr_sort_keys=выкл., outer_join_with_cache=вкл., semijoin_with_cache=вкл., join_cache_incremental=вкл., join_cache_hashed=вкл., join_cache_bka=вкл., optimize_join_buffer_size=выкл., table_elimination=вкл. |
| MariaDB 5.3.0 | index_merge=вкл., index_merge_union=вкл., index_merge_sort_union=вкл., index_merge_intersection=вкл., index_merge_sort_intersection=выкл., index_condition_pushdown=выкл., derived_merge=выкл., derived_with_keys=выкл., firstmatch=выкл., loosescan=выкл., materialization=выкл., in_to_exists=вкл., semijoin=выкл., partial_match_rowid_merge=вкл., partial_match_table_scan=вкл., subquery_cache=выкл., mrr=выкл., mrr_cost_based=выкл., mrr_sort_keys=выкл., outer_join_with_cache=выкл., semijoin_with_cache=выкл., join_cache_incremental=вкл., join_cache_hashed=вкл., join_cache_bka=вкл., optimize_join_buffer_size=выкл., table_elimination=вкл. |
| < MariaDB 5.3.0 | index_merge=вкл., index_merge_union=вкл., index_merge_sort_union=вкл., index_merge_intersection=вкл. |
См. также
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https://mariadb.com/kb/en/optimizer-switch/
