i have a cluster of 2 nodes (version 1.7.2 running on java 1.8.0_45).
i have changed the thread pool bulk queue size from 50 to 250.
Under heavy bulk indexing load, i have seen via the cat API a "weird" behavior:
"bulk active" pool are both used, but only one queue_size has got a high value (116 for example)...
the other queue size is flat ( from 0 to 5 ....)
Is It a normal behavior?
Why Elasticsearch fill preferentially one queue ?