RocksDB 读 cpu 100% 如何调优

[Peihui He <pe...@gmail.com>]

Hi, all

如题，flink 任务使用rocksdb 做为状态后端，任务逻辑大概意思是：
来一条数据先判断该数据的key 是否再mapstat 中， 然后再将该key 写入mapstat中。

产生问题是当数据跑一段时间后，判断是否存在线程cpu总是100%，堆栈如下：

"process (6/18)#0" Id=80 RUNNABLE (in native)
    at org.rocksdb.RocksDB.get(Native Method)
    at org.rocksdb.RocksDB.get(RocksDB.java:2084)
    at
org.apache.flink.contrib.streaming.state.RocksDBMapState.contains(RocksDBMapState.java:173)
    at
org.apache.flink.runtime.state.UserFacingMapState.contains(UserFacingMapState.java:72)
    at
com.huanju.security.soc.internal.hs.bigdata.FileScanToTiDB$$anon$12.processElement(FileScanToTiDB.scala:156)
    at
com.huanju.security.soc.internal.hs.bigdata.FileScanToTiDB$$anon$12.processElement(FileScanToTiDB.scala:145)
    at
org.apache.flink.streaming.api.operators.KeyedProcessOperator.processElement(KeyedProcessOperator.java:83)
    at
org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.emitRecord(OneInputStreamTask.java:233)
    at
org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.processElement(AbstractStreamTaskNetworkInput.java:134)
    at
org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.emitNext(AbstractStreamTaskNetworkInput.java:105)
    at
org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65)
    at
org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:496)
    at
org.apache.flink.streaming.runtime.tasks.StreamTask$$Lambda$624/715942770.runDefaultAction(Unknown
Source)
    at
org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:203)
    at
org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:809)
    at
org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:761)
    at
org.apache.flink.runtime.taskmanager.Task$$Lambda$773/520411616.run(Unknown
Source)
    at
org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:958)
    at
org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:937)
    at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:766)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:575)
    at java.lang.Thread.run(Thread.java:748)

但是看checkpoint数据，才100m左右

请问大家 rocksdb 是出现什么性能瓶颈了呢？ 改怎么调优呢？