class Book {
...
static mapping = {
batchSize 10
}
}
batchSize
Purpose
Customizes how many results are fetching during lazy loading.
Examples
Description
Usage: batchSize(integer)
Given a lazy association where an Author
has many Book
instances, GORM will perform one query for the Author
and additional queries the associated Book
instances. 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
}
You can also configure batchSize
on a per association basis:
class Author {
static hasMany = [books: Book]
static mapping = {
books batchSize: 10
}
}