[ https://issues.apache.org/jira/browse/ARROW-5917?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Micah Kornfield resolved ARROW-5917. ------------------------------------ Fix Version/s: 0.15.0 Resolution: Fixed Issue resolved by pull request 4994 [https://github.com/apache/arrow/pull/4994] > [Java] Redesign the dictionary encoder > -------------------------------------- > > Key: ARROW-5917 > URL: https://issues.apache.org/jira/browse/ARROW-5917 > Project: Apache Arrow > Issue Type: New Feature > Components: Java > Reporter: Liya Fan > Assignee: Liya Fan > Priority: Major > Labels: pull-request-available > Fix For: 0.15.0 > > Time Spent: 12h 20m > Remaining Estimate: 0h > > The current dictionary encoder implementation > (org.apache.arrow.vector.dictionary.DictionaryEncoder) has heavy performance > overhead, which prevents it from being useful in practice: > # There are repeated conversions between Java objects and bytes (e.g. > vector.getObject(i)). > # Unnecessary memory copy (the vector data must be copied to the hash table). > # The hash table cannot be reused for encoding multiple vectors (other data > structure & results cannot be reused either). > # The output vector should not be created/managed by the encoder (just like > in the out-of-place sorter) > # The hash table requires that the hashCode & equals methods be implemented > appropriately, but this is not guaranteed. > We plan to implement a new one in the algorithm module, and gradually > deprecate the current one. -- This message was sent by Atlassian Jira (v8.3.4#803005)