hashmap.h | # ️⃣ single header hashmap implementation for C and C++ | Map library

The comments in the code say:

"Implementation note: This is a simple linear-probe hash table, as described for example in texts by Sedgewick and Knuth. The array alternates holding keys and values."

In fact the the hash method returns a value that is used as a direct index into the array. For example:

The problem here is that determining the hashCode of the data class instance is leading to a stackoverflow error due to the bidirectional association (mutual references).

To avoid this you need to exclude the @ManyToMany properties from the hashCode method (e.g. by explicitly declaring hashCode on your own).

Property include/exclude on Kotlin data classes

The way to define a member of a template class is

This is because you are using the @EqualsAndHashCode Lombok annotation. There is an error (possibly recursive, since your stack trace is large, I am not sure) when getting the hashcode of the Review JPA entity.

The Lombok auto-generated hashcode method in Review entity will call the Book entity, which tries to get the hashcode of the Set of Reviews. This Set needs to be initialized first before it can be read.

The Flink metrics you are looking at only measure traffic happening within the Flink cluster itself (using Flink's serializers and network stack), and ignore the communication at the edges of the job graph (using the connectors' serializers and networking).

In other words, sources never report records coming in, and sinks never report records going out.

Furthermore, in your job all of the operators can be chained together, so Flink's network is not used at all.

Yes, this is confusing.

The leak is actually a bug in the navigation compose library and a fix will be available with the next release: https://issuetracker.google.com/issues/204905432#comment4

Concisely: Using

After several tries, we found the problem and the solution: Standalone docker job just submit the job but never gets started.

In order to solve this, we need to create 2 extra containers, one for job manager and one for task manager:

From the docs for Index:

container[index] is actually syntactic sugar for *container.index(index)

So what happens is that when you write m["aaa"], the compiler is actually adding a * that dereferences the value returned by Index::index, whereas when you call m.index ("aaa"), you get the &String reference directly.

As pointed out by @user4815162342, programmers are supposed to make their intent explicit by writing either &m["aaa"] or m["aaa"].clone().

Moreover println!("{:?}", m["aaa"]); works because the println! macro does add a & to all the values it accesses¹ to prevent accidental moves caused by display, and this cancels out the * added by the compiler.

(1) This is indirectly documented in the docs for the format_args! macro.