batchSize
目的 Purpose
Customizes how many results are fetching during lazy loading.使用例 Examples
class Book {
…
static mapping = {
batchSize 10
}
}
詳細 Description
Usage:
使用方法: batchSize(integer)
Usage:
batchSize(integer)
Given a lazy association where an Author
has many Book
s, GORM will perform one query for the Author
and additional queries the associated Book
s. This is what is known as the N+1 problem and can often be worked around by using a join query. However, joins can be expensive.Batch fetching is an optimization of lazy loading so that if, for example, you set a batchSize
of 10 and you have an Author
that with 30 books, instead of 31 queries you get four (one for the Author
and three batches of 10):static mapping = {
batchSize 10
}
batchSize
on a per association basis:class Author { static hasMany = [books: Book] static mapping = { books batchSize: 10 } }