FORCE INDEX in MySQL - where do I put it? - Stack Overflow
FORCE INDEX is going to be deprecated after MySQL 8: Thus, you should expect USE INDEX, FORCE INDEX, and IGNORE INDEX to be deprecated in a future release of MySQL, and at some time thereafter to be removed altogether. You should be using JOIN_INDEX, GROUP_INDEX, ORDER_INDEX, and INDEX instead, for v8.
sql - Force index use in Oracle - Stack Overflow
2009年12月3日 · There is a table which has a index on a column, and you query: select * from table_name where column_having_index="some value"; The query takes too long, and you find out that the index is not being used. If you think the performance of the query will be better using the index, how could you force the query to use the index?
sql - How to use index in select statement? - Stack Overflow
2011年7月6日 · Usually the DB engine should automatically select the index to use based on query execution plans it builds. However, there are some pretty rare cases when you want to force the DB to use a specific index. To be able to answer your specific question you have to specify the DB you are using.
How do I force Postgres to use a particular index?
In other words, what might be a good query plan today probably won't be a good query plan for all time, and index hints force a particular query plan for all time. As a very blunt hammer, useful for testing, you can use the enable_seqscan and enable_indexscan parameters. See: Examining index usage; enable_ parameters
MySQL : FORCE INDEX vs USE INDEX - Stack Overflow
If you use USE INDEX then you RECOMMEND optimizer to use this index, but it can use a table scan if optimizer thinks it will be faster. If you use FORCE INDEX then you MAKE optimizer to use this index even if it thinks a table scan is more efficient. Optimizer will use a table scan only if there is no way to use index to find rows. –
How to force an index on inner joined tables? - Stack Overflow
2011年2月7日 · From MySQL 4.0.9 on, you can also use FORCE INDEX, which acts like USE INDEX (index_list) but with the addition that a table scan is assumed to be very expensive. In other words, a table scan is used only if there is no way to use one of the given indexes to find rows in the table.
How can I force a query to not use a index on a given table?
2013年9月17日 · This ensures the test code won't use the index but prevents the index from actually being disabled. BEGIN TRANSACTION ALTER INDEX [MyIndex] ON MyTable DISABLE; EXEC TestCode; ROLLBACK This works better if you've got a complex case where your test code uses a number of indexes at different times and you want to test if the addition of a new …
How do you force a query in MySQL to use an index?
2014年11月17日 · You can also use FORCE INDEX, which acts like USE INDEX(index_list) but with the addition that a table scan is assumed to be very expensive. In other words, a table scan is used only if there is no way to use one of the given indexes to find rows in the table. Each hint requires the names of indexes, not the names of columns.
What is the syntax to force the use of an index for a join in MySQL
2009年8月13日 · The FORCE/USE/IGNORE goes after the table name you are joining, and after the alias if you're using one. SELECT t1.`id` AS `id_1`, t2.`id` AS `id_2` FROM `table1` t1 LEFT OUTER JOIN `table2` t2 FORCE INDEX FOR JOIN (`table1_id`) ON (t2.`table1_id` = t1.`id`)
php - laravel how to use force index in eloquent - Stack Overflow
2018年3月30日 · SELECT * FROM orders FORCE INDEX(order_type_index) WHERE `type` = 1 I can use query builder to recreate this: