When I run `DELETE` operation with `spring-r2dbc` ...

# spring

[Robert Jaros]

When I run DELETE operation with spring-r2dbc and coroutines, by using such code inside a suspending function:

databaseClient.execute("DELETE FROM tab WHERE field = :field").bind("field", 5).then().awaitFirstOrNull()

Spring Boot gives me the following exception in logs:

2019-09-12 19:52:05,849 [reactor-tcp-epoll-3] ERROR i.r.p.client.ReactorNettyClient - Connection Error
io.netty.util.IllegalReferenceCountException: refCnt: 0
        at io.netty.buffer.AbstractByteBuf.ensureAccessible(AbstractByteBuf.java:1464)
        at io.netty.buffer.CompositeByteBuf.discardReadComponents(CompositeByteBuf.java:1733)
        at io.r2dbc.postgresql.message.backend.BackendMessageEnvelopeDecoder.lambda$apply$0(BackendMessageEnvelopeDecoder.java:69)
        at reactor.core.publisher.FluxCreate.subscribe(FluxCreate.java:94)
        at reactor.core.publisher.Flux.subscribe(Flux.java:8127)

It looks like some kind of resource leak warning, because my code is running fine and SQL statement is executed correctly.
If I run:

databaseClient.delete().from("tab").matching(where("field").`is`(5)).then().awaitFirstOrNull()

there is no exception. And there are no problems with other kind of queries (SELECT, INSERT, UPDATE).
Is this my bug? Or is this probably a bug in spring boot or spring-r2dbc?

[sdeleuze]

Does the same code runs fine with Reactive API ?
Unrelated, but any reason to use then().awaitFirstOrNull() instead of the provide extensions?

[sdeleuze]

And what version of Boot + Spring Data R2DBC are you using?

[Robert Jaros]

I'm not using reactive api, so I'm not sure and I'm not really know how to check this.
What should I use instead of then().awaitFirstOrNull() to execute the statement and suspend until it is done?
I'm using:
Spring Boot 2.2.0.BUILD-SNAPSHOT
Spring Data R2DBC 1.0.0.BUILD-SNAPSHOT
r2dbc-postgresql 0.8.0.BUILD-SNAPSHOT
(the only combination that works for me at the moment)

[sdeleuze]

https://github.com/spring-projects/spring-fu/blob/master/samples/kofu-coroutines-r2dbc/src/main/kotlin/com/sample/Repositories.kt

[sdeleuze]

Try .fetch().awaitOneOrNull maybe

[sdeleuze]

We provide Kotlin extensions

[sdeleuze]

For Coroutines directly

[sdeleuze]

It lacks of documentation for now

[Robert Jaros]

Apparently the problem solved itself ...
Gradle downloaded some new snapshots and the exception is gone 🙂
Thx for your support anyway.

[Robert Jaros]

One more question - is there any significant difference in using await* kotlin extensions from spring-data and await* extensions from coroutines.rective?

[Robert Jaros]

I haven't even noticed I'm mixing those extensions in my code until your question

[sdeleuze]

Nope they are just shortcuts