调用saveAll 时我的方法JpaRepository很长List<Entity>从服务层来看，Hibernate 的跟踪日志显示每个实体发出的单个 SQL 语句。

我可以强制它进行批量插入(即多行)而不需要手动摆弄 EntityManger 、事务等，甚至是原始 SQL 语句字符串？

对于多行插入，我的意思不仅仅是从:

start transaction
INSERT INTO table VALUES (1, 2)
end transaction
start transaction
INSERT INTO table VALUES (3, 4)
end transaction
start transaction
INSERT INTO table VALUES (5, 6)
end transaction

到:

start transaction
INSERT INTO table VALUES (1, 2)
INSERT INTO table VALUES (3, 4)
INSERT INTO table VALUES (5, 6)
end transaction

但改为:

start transaction
INSERT INTO table VALUES (1, 2), (3, 4), (5, 6)
end transaction

在 PROD 中，我使用的是 CockroachDB，性能差异很大。

以下是重现问题的最小示例(为简单起见，H2)。

./src/main/kotlin/ThingService.kt :

package things

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.web.bind.annotation.RestController
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.data.jpa.repository.JpaRepository
import javax.persistence.Entity
import javax.persistence.Id
import javax.persistence.GeneratedValue

interface ThingRepository : JpaRepository<Thing, Long> {
}

@RestController
class ThingController(private val repository: ThingRepository) {
    @GetMapping("/test_trigger")
    fun trigger() {
        val things: MutableList<Thing> = mutableListOf()
        for (i in 3000..3013) {
            things.add(Thing(i))
        }
        repository.saveAll(things)
    }
}

@Entity
data class Thing (
    var value: Int,
    @Id
    @GeneratedValue
    var id: Long = -1
)

@SpringBootApplication
class Application {
}

fun main(args: Array<String>) {
    runApplication<Application>(*args)
}

./src/main/resources/application.properties :

jdbc.driverClassName = org.h2.Driver
jdbc.url = jdbc:h2:mem:db
jdbc.username = sa
jdbc.password = sa

hibernate.dialect=org.hibernate.dialect.H2Dialect
hibernate.hbm2ddl.auto=create

spring.jpa.generate-ddl = true
spring.jpa.show-sql = true

spring.jpa.properties.hibernate.jdbc.batch_size = 10
spring.jpa.properties.hibernate.order_inserts = true
spring.jpa.properties.hibernate.order_updates = true
spring.jpa.properties.hibernate.jdbc.batch_versioned_data = true

./build.gradle.kts :

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile

plugins {
    val kotlinVersion = "1.2.30"
    id("org.springframework.boot") version "2.0.2.RELEASE"
    id("org.jetbrains.kotlin.jvm") version kotlinVersion
    id("org.jetbrains.kotlin.plugin.spring") version kotlinVersion
    id("org.jetbrains.kotlin.plugin.jpa") version kotlinVersion
    id("io.spring.dependency-management") version "1.0.5.RELEASE"
}

version = "1.0.0-SNAPSHOT"

tasks.withType<KotlinCompile> {
    kotlinOptions {
        jvmTarget = "1.8"
        freeCompilerArgs = listOf("-Xjsr305=strict")
    }
}

repositories {
    mavenCentral()
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web")
    compile("org.springframework.boot:spring-boot-starter-data-jpa")
    compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    compile("org.jetbrains.kotlin:kotlin-reflect")
    compile("org.hibernate:hibernate-core")
    compile("com.h2database:h2")
}

运行:

./gradlew bootRun

触发数据库插入:

curl http://localhost:8080/test_trigger

日志输出:

Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: select thing0_.id as id1_0_0_, thing0_.value as value2_0_0_ from thing thing0_ where thing0_.id=?
Hibernate: call next value for hibernate_sequence
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)
Hibernate: insert into thing (value, id) values (?, ?)

最佳答案

要使用 Spring Boot 和 Spring Data JPA 进行批量插入，您只需要两件事:

1. 将选项 spring.jpa.properties.hibernate.jdbc.batch_size 设置为您需要的适当值(例如:20)。

2. 使用你的 repo 的 saveAll() 方法和准备插入的实体列表。

工作示例是 here .

关于插入语句的转换成这样的:

INSERT INTO table VALUES (1, 2), (3, 4), (5, 6)

PostgreSQL 中提供了这样的功能:您可以在 jdbc 连接字符串中将选项 reWriteBatchedInserts 设置为 true:

jdbc:postgresql://localhost:5432/db?reWriteBatchedInserts=true

然后jdbc驱动会做this transformation .

您可以找到有关批处理的其他信息 here .

更新

Kotlin 中的演示项目:sb-kotlin-batch-insert-demo

更新

Hibernate disables insert batching at the JDBC level transparently if you use an IDENTITY identifier generator.

https://stackoverflow.com/questions/50772230/