[ARROW-5100] [JS] Writer swaps byte order if buffers share the same underlying ArrayBuffer

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.13.0
• Fix Version/s: 0.14.0
• Component/s: JavaScript
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/21587
• Assignee: Paul Taylor
• Reporter: Paul Taylor
• Due: 02/Apr/19
• Created: 03/Apr/19 06:58
• Updated: 11/Jan/23 07:38
• Resolved: 12/Apr/19 18:20

Description

We collapse contiguous Uint8Arrays that share the same underlying ArrayBuffer and have overlapping byte ranges. This was done to maintain true zero-copy behavior when using certain node core streams that use a buffer pool internally, and could write chunks of the same logical Arrow Message at out-of-order byte offsets in the pool.

Unfortunately this can also lead to a bug where, in rare cases, buffers are swapped while writing Arrow Messages too. We could have a flag to indicate whether we think collapsing out-of-order same-buffer chunks is safe, but I'm not sure if we can always know that, so I'd prefer to take it out and incur the copy cost.

Issue Links

• links to: GitHub Pull Request #4102