[IGNITE-7931] Wrong arguments for ConcurrentHashMap

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 2.5
• Assignee: Ivan Fedotov
• Reporter: Ivan Fedotov
• Created: 13/Mar/18 10:58
• Updated: 02/Apr/18 19:09
• Resolved: 02/Apr/18 19:07

Description

When creating ConcurrentHashMap:

BinaryUtils.java

new ConcurrentHashMap<>(U.capacity((map).size()));

[1], [2] `U.capacity` returns capacity that is sufficient to keep the map from being resized. In ConcurrentHashMap this is unnecessary because recalculation already performs in the constructor.
Similar problem in GridConcurrentHashSet because inside it implements ConcurrentHashMap:

DataStreamerImpl.java

keys = new GridConcurrentHashSet<>(entries.size(), U.capacity(entries.size()), 1);

[3],[4] result of `U.capacity` is passed as `loadFactor` value. When loadFactor == U.capacity, initial size of table is 1.
This leads to performance penalty due to rehashing of internal map.

 

[1]https://github.com/1vanan/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/binary/BinaryUtils.java#L670

[2]https://github.com/1vanan/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/binary/BinaryUtils.java#L688

[3]https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/datastreamer/DataStreamerImpl.java#L633

[4]https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/datastreamer/DataStreamerImpl.java#L574

Issue Links

• links to: GitHub Pull Request #3646
• links to: TeamCity