[PARQUET-1855] [C++] Improve documentation on MetaData ownership

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: cpp-4.0.0
• Component/s: parquet-cpp
• Labels: pull-request-available
• Assignee: Francois Saint-Jacques
• Reporter: Francois Saint-Jacques
• Created: 04/May/20 15:32
• Updated: 24/May/20 20:11
• Resolved: 24/May/20 20:11

Description

I had to look at the implementation to understand what are the lifetime relationship for the following objects:

• FileMetaData
• RowGroupMetaData
• ColumnChunkMetaData

From what I gather, a reference to the top-level FileMetaData must be hold for any of the children objects (RowGroupMetaData and ColumnChunkMetaData) lifetime. It is unclear if the original buffer from which the metadata was deserialized must be hold for the lifetime of the FIleMetaData object, I suspect it does not need to be kept.

Issue Links

• links to: GitHub Pull Request #7244