[ARROW-360] C++: Add method to shrink PoolBuffer using realloc

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.2.0
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/15902
• Assignee: Uwe Korn
• Reporter: Uwe Korn
• Created: 03/Nov/16 10:47
• Updated: 11/Jan/23 07:08
• Resolved: 07/Jan/17 21:29

Description

In the case where we have optimistically allocated a large PoolBuffer, we could shrink it later again using a call to realloc. This should free the exceeding memory but avoids an actual memcpy.

Issue Links

• is depended upon by: PARQUET-761 C++: Shrink using realloc Buffer instead of doing a memcpy in FlatColumnReader::Impl::TypedReadBatch