I've come across a similar issue before, the reason is that for a dynamic
link library(so/dll), the there can only be one classloader to load it.
When restart/failover happens in flink, the JVM will not exit but only
create a new classloader which leads to multiple loading to the same
so/dll, here
Hi, it's because the Outer Joins will generate retractions, consider the
behavior of Left Outer Join
1. left record arrives, no matched right record, so +(left, null) will be
generated.
2 right record arrives, the previous result should be retracted, so
-(left, null) and +(left, right) will be
