Jason Gustafson created KAFKA-3014:
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Summary: Integer overflow causes incorrect node iteration in
leastLoadedNode()
Key: KAFKA-3014
URL: https://issues.apache.org/jira/browse/KAFKA-3014
Project: Kafka
Issue Type: Bug
Reporter: Jason Gustafson
Assignee: Jason Gustafson
The leastLoadedNode() implementation iterates over all the known nodes to find
a suitable candidate for sending metadata. The loop looks like this:
{code}
for (int i = 0; i < nodes.size(); i++) {
int idx = Utils.abs((this.nodeIndexOffset + i) % nodes.size());
Node node = nodes.get(idx);
...
}
{code}
Unfortunately, this doesn't handle integer overflow correctly, which can result
in some nodes in the list being passed over. For example, if the size of the
node list is 5 and the random offset is Integer.MAX_VALUE, then the loop will
iterate over the following indices: 2, 3, 2, 1, 0.
In pathological cases, this can prevent the client from being able to connect
to good nodes in order to refresh metadata.
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