New features
USE INDEX
, FORCE INDEX
and IGNORE INDEX
for MySQL
In MySQL, the statements USE INDEX, FORCE INDEX, and IGNORE INDEX are hints used in SQL queries to influence how the query optimizer selects indexes. These hints provide fine-grained control over index usage, helping optimize performance when the default behavior of the optimizer is not ideal.
Use Index
The USE INDEX
hint suggests to the optimizer which indexes to consider when processing the query. The optimizer is not forced to use these indexes but will prioritize them if they are suitable.
export const users = mysqlTable('users', {
id: int('id').primaryKey(),
name: varchar('name', { length: 100 }).notNull(),
}, () => [usersTableNameIndex]);
const usersTableNameIndex = index('users_name_index').on(users.name);
await db.select()
.from(users, { useIndex: usersTableNameIndex })
.where(eq(users.name, 'David'));
Ignore Index
The IGNORE INDEX
hint tells the optimizer to avoid using specific indexes for the query. MySQL will consider all other indexes (if any) or perform a full table scan if necessary.
export const users = mysqlTable('users', {
id: int('id').primaryKey(),
name: varchar('name', { length: 100 }).notNull(),
}, () => [usersTableNameIndex]);
const usersTableNameIndex = index('users_name_index').on(users.name);
await db.select()
.from(users, { ignoreIndex: usersTableNameIndex })
.where(eq(users.name, 'David'));
Force Index
The FORCE INDEX
hint forces the optimizer to use the specified index(es) for the query. If the specified index cannot be used, MySQL will not fall back to other indexes; it might resort to a full table scan instead.
export const users = mysqlTable('users', {
id: int('id').primaryKey(),
name: varchar('name', { length: 100 }).notNull(),
}, () => [usersTableNameIndex]);
const usersTableNameIndex = index('users_name_index').on(users.name);
await db.select()
.from(users, { forceIndex: usersTableNameIndex })
.where(eq(users.name, 'David'));
You can also combine those hints and use multiple indexes in a query if you need