thisAmateur opened a new issue, #5147:
URL: https://github.com/apache/servicecomb-java-chassis/issues/5147
### Steps to Reproduce
### 环境信息：
我们业务现网用的jdk：
bisheng jdk 21.0.10+7
我本地用的jdk：
openjdk version "21.0.8" 2025-07-15 LTS
OpenJDK Runtime Environment Microsoft-11933218 (build 21.0.8+9-LTS)
useG1GC
### 问题场景：
微服务A调微服务B的一个sse接口，其中微服务A是一个edge服务。
当这个sse接口的响应报文比较大的时候，比如累计几十KB或者几百KB时，微服务A就会容易触发OOM错误。
微服务A的OOM报错堆栈：
```properties
java.lana.Error: java.lang.reflect.InvocationTargetException
at
io.netty.util.internal.PlatformDependentO.allocateUninitializedArray(PlatformDependent0.java:718)
at
io.netty.util.internal.PlatformDependent.allocateUninitializedArray(PlatformDependent.java:329)
at
io.netty.buffer.UnpooledUnsafeHeapByteBuf.allocateArray(UnpooledUnsafeHeapByteBuf,java:
39)
at io.netty.buffer.AbstractByteBuf.ensureWritable0
(AbstractByteBuf.java: 305)
at
io.netty.buffer.AbstractByteBuf.ensureWritable0(AbstractByteBuf.java: 305)
at
io.netty.buffer.AbstractByteBuf.ensureWritable(AbstractByteBuf.java:280)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1081)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.readALineOfBytesFromBuffer(ProduceEventStreamProcessor.java:339)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.processAllAvailableBufferLines
(ProduceEventStreamProcessor.java:260)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.bufferReadCacheAndProcessLines
(ProduceEventStreamProcessor.java:175)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.bufferReadCacheAndProcessLines
(ProduceEventStreamProcessor.java:175)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.innerLoop(ProduceEventStreamProcessor.java:157)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.doDecodeResponse
(ProduceEventStreamProcessor.java:125)
at
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor.decodeResponse
(ProduceEventStreamProcessor.java:395)
at
org.apache.servicecomb.transport.rest.client.http.DefaultHttpClientFilter.extractFlowableBody(DefaultHttpClientFilter.java:157)
at
org.apache.servicecomb.transport.rest.client.http.DefaultHttpClientFilter.lambda$extractResponse$0
(DefaultHttpClientFilter.java: 119)
at
io.reactivex.rxjava3.internal.operators.flowable.FlowableConcatMap$ConcatMapImmediate.drain(FlowableConcatMap.java:
265)
at
io.reactivex.rxjava3.internal.operators.flowable.FlowableConcatMap$BaseConcatMapSubscriber.onNext(FlowableConcatMap.java:158)
at
io.vertx.rxjava3.impl.FlowableReadStream.lambda$subscribeActual$2(FlowableReadStream.java:83)
at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:270)
at
io.vertx.core.http.impl.HttpEventHandler.handleChunk(HttpEventHandler.java:51)
at
io.vertx.core.http.impl.HttpEventHandler.handleChunk(HttpEventHandler.java:51)
at
io.vertx.core.http.impl.HttpClientResponseImpl.handleChunk(HttpClientResponseImpl.java:239)
at
io.vertx.core.http.impl.HttplxClientConnection$StreamImpl.lambda$new$0(HttplxClientConnection.java:456)
at
io.vertx.core.streams.impl.InboundBuffer.handleEvent(InboundBuffer.java:279)
at
io.vertx.core.http.impl.Http1xClientConnection$StreamImpl.handleChunk(HttplxClientConnection.java:754)
at
io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
at
io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.
java:166)
at
io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:566)
at
io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:998)
at
io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at
io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:
30)
at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
at
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at
io.netty.util.internal.PlatformDependentO.allocateUninitializedArray(PlatformDependent0.java:
714)
... 36 more
Caused by: java.lang.OutOfMemoryError: Java heap space
at
java.base/jdk.internal.misc.Unsafe.allocateUninitializedArray(Unknown Source)
at
java.base/java.lang.invoke.DirectMethodHandle$Holder.invokeSpecial(DirectMethodHandle$Holder)
at
java.base/java.lang.invoke.LambdaForm$MH/0x0000007801fc8c00.invoke(LambdaForm$MH)
at
java.base/java.lang.invoke.LambdaForm$MH/0x0000007801002800.invokeExact_MT(LambdaForm$MH)
```
### 问题分析：
org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor#doDecodeResponse中定义个一个128长度的buffer，来从网络流中读数据。while中每读一次，就会走到处理方法中处理。当后端服务返回的数据比较大的时候，128长度里，肯定是没有换行的。需要读非常多次，才能读到换行。
然后
在org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor#readALineOfBytesFromBuffer
这个类里，在匹配一个新行的时候，如果没匹配到，会把已经读过的字节数组数据，重新写回到org.apache.servicecomb.common.rest.codec.produce.ProduceEventStreamProcessor#buffer中，导致buffer的空间急剧膨胀。
实测后端返回170KB左右的报文，这个buffer会占用56MB左右的空间。
这部分空间，在jvm中直接分配到了humongous
region，而我们sse接口，往往一次请求，返回的时间还比较长，当这种大响应的请求并发比较多的时候，jvm堆中老年代内存直接就满了。从而触发OOM。
### Expected Behavior
预期服务正常运行，SSE场景下，ProduceEventStreamProcessor中的变量都分配在eden区，通过younggc即可快速回收，不会导致老年代满，不会导致OOM
### Servicecomb Version
2.9.3
### Additional Context
_No response_
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