R2DBC history 및 issue

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개요

Reactive Relational Database Connectivity
SQL database에서 Reactive programming을 지원하기 위해 디자인된 새로운 Open Specification
R2DBC를 쉽게 사용할 수 있도록 ORM의 사용법을 참고하여 설계하였으나, ORM Framework에서 제공하는 다양한 기능을 제공하지 않음. 

 

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특징

Based on the Reactive Streams specification. 
 - provides a fully-reactive non-blocking API.

Works with relational databases.
 - JDBC의 Blocking 특성과 달리, R2DBC를 사용하면 Reactive API를 사용하여 SQL database로 작업할 수 있다.

Supports scalable solutions.
 - Reactive Stream을 사용하면 기존의 "연결 당 하나의 스레드"모델에서보다 강력하고 확장 가능한 접근 방식이 가능하다.

Provides an open specification.
 - R2DBC 는 open specification이며 드라이버 공급업체가 spec을 구현하고 클라이언트가 사용할 SPI(Service Provider Interface) 제공합니다.
 - R2DBC는 최소한의 SPI를 목표로 한다. 

 

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구현체

clickhouse-r2dbc - R2DBC wrapper of async Java client for ClickHouse.
cloud-spanner-r2dbc - driver for Google Cloud Spanner.
jasync-sql - R2DBC wrapper for Java & Kotlin Async Database Driver for MySQL and PostgreSQL (written in Kotlin).
oracle-r2dbc - native driver implemented for Oracle.
r2dbc-h2 - native driver implemented for H2 as a test database.
r2dbc-mariadb - native driver implemented for MariaDB.
r2dbc-mssql - native driver implemented for Microsoft SQL Server.
r2dbc-mysql - native driver implemented for MySQL (previously mirromutth/r2dbc-mysql).
r2dbc-postgresql - native driver implemented for PostgreSQL.

 

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SPI History ~ 1.0

0.8

• initial version

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0.9

• Extended transaction definitions
• Improved Bind Parameter declararation
• Consumption of OUT Parameters
• Consumption of Result Segments
• Lifecycle extension
• Refinement of Option
• Refinement of RowMetadata
• Lock Wait and Statement Timeouts
• Refined Exceptions for Readable.get(…) and Statement.bind(…)

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1.0

• Revised Result.getRowsUpdated() signature
  • 1.0 스펙 중 이전 버전이랑 하위호환이 안되게 하는 주범, update 시 update row를 Long -> Integer로 변경해서, update(save) 시 classCastException이 발생한다.
• Removed RowMetadata.getColumnNames() method
• TCK Extensions

 

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Spring Data R2DBC

Spring Data R2DBC version	imported R2DBC SPI version	주요 기능
1.0.0	0.8	initial major version
1.1.0	0.8.1	r2dbcEntityTemplate 기능 추가 query derivation 추가
1.2.0	0.8.3	r2dbcAuditing 추가 @Value support support Oracle R2DBC Driver
1.3.0	0.8.4	Query By Example 기능 추가
1.4.0	0.8.5	upgrade dependency
1.5.0	0.9.1	upgrade dependency
3.0.0	1.0.0	spring boot 3 대응

Spring Boot Starter Data R2DBC version	Spring Data R2DBC version
2.3.2	1.1.2
2.4.0	1.2.1
2.5.0	1.3.1
2.6.0	1.4.0
2.7.0	1.5.0
3.0.0	3.0.0

 

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MySQL, MariaDB Driver

관련 드라이버

DB Type	Driver	develop by	Desc
Mysql	jasync-sql	jasync-sql	코틀린으로 개발된 드라이버 MySQL, PostgreSQL 지원
	r2dbc-mysql	mirrormutth	최초의 mysql r2dbc driver 구현체 현재는 개발 중단
	r2dbc-mysql	asyncer-io	mysql 5.5, 5.6, 5.7, 8.0 호환 r2dbc-spi 1.0까지 호환
MariaDB	mariadb-connector-r2dbc	mariadb-corp	MariaDB 공식 r2dbc 지원 드라이버

 

MySQL 계열 사용 시 공식드라이버인 MariaDB를 사용하는 것이 안정적 일 듯하다

 

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주저리주저리

• 신규 프로젝트에서 R2DBC 사용 도중 update 시 driver에서 오류가 올라와서 부랴부랴 알아봄.
• SPI 1.0 버전이 나온 것까진 알고 있었는데 interface상 하위호환이 안될 줄은 상상도 못 함...
• 일단 버전에 맞는 mariaDB 구현체를 사용해서 해결한 상태.
• 이슈 해결 후 조사한 게 억울해서 블로그에 정리

이슈 stacktrace

20230421 14:59:18.570 [db-sql-netty-thread-2] ERROR o.s.b.a.w.r.e.AbstractErrorWebExceptionHandler - [695cf522-1]  500 Server Error for HTTP PUT "/dev/data" 
java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer (java.lang.Long and java.lang.Integer are in module java.base of loader 'bootstrap')
	at java.base/java.util.stream.Collectors.lambda$summingInt$19(Collectors.java:673)
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ Handler org.springframework.web.reactive.function.server.RouterFunctionDsl$PUT$2@10647471 [DispatcherHandler]
	*__checkpoint ⇢ com.pbear.mainfunctionalserver.common.log.LoggingWebFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP PUT "/dev/data" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at java.base/java.util.stream.Collectors.lambda$summingInt$19(Collectors.java:673)
		at reactor.core.publisher.MonoStreamCollector$StreamCollectorSubscriber.onNext(MonoStreamCollector.java:132)
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.tryEmitScalar(FluxFlatMap.java:489)
		at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:422)
		at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
		at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79)
		at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:282)
		at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:863)
		at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1839)
		at reactor.core.publisher.MonoCompletionStage.lambda$subscribe$0(MonoCompletionStage.java:96)
		at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:930)
		at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:907)
		at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
		at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073)
		at com.github.jasync.sql.db.util.FutureUtilsKt.success(FutureUtils.kt:16)
		at com.github.jasync.sql.db.mysql.MySQLConnection.succeedQueryPromise$lambda-12(MySQLConnection.kt:361)
		at java.base/java.util.Optional.ifPresent(Optional.java:183)
		at com.github.jasync.sql.db.mysql.MySQLConnection.succeedQueryPromise(MySQLConnection.kt:360)
		at com.github.jasync.sql.db.mysql.MySQLConnection.onOk(MySQLConnection.kt:227)
		at com.github.jasync.sql.db.mysql.codec.MySQLConnectionHandler.channelRead0(MySQLConnectionHandler.kt:125)
		at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
		at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:346)
		at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:318)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
		at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440)
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
		at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
		at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
		at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788)
		at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724)
		at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650)
		at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562)
		at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
		at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
		at java.base/java.lang.Thread.run(Thread.java:834)

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REFERENCE

https://r2dbc.io/

https://docs.spring.io/spring-data/r2dbc/docs/current/reference/html/

https://r2dbc.io/spec/1.0.0.RELEASE/spec/html/#changes

https://stackoverflow.com/questions/74972672/java-lang-integer-cannot-be-cast-to-class-java-lang-long-in-r2dbc-mysql-model-cl

https://github.com/spring-projects/spring-data-commons/wiki/Release-Trains