[ARROW-2294] [Java] Fix splitAndTransfer for variable width vector

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Java
• External issue URL: https://github.com/apache/arrow/issues/18248
• Assignee: Unassigned
• Reporter: Siddharth Teotia
• Created: 09/Mar/18 20:34
• Updated: 11/Jan/23 07:20

Description

When we splitAndTransfer a vector, the value count to set for the target vector should be equal to split length and not the value count of source vector. 

We have seen cases in operator slike FLATTEN and under low memory conditions, we end up allocating a lot more memory for the target vector because of using a large value in setValueCount after split and transfer is done.