[ARROW-16177] [C++] Replace ThreadIndexer with a more performant thread-local implementation

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/31580
• Assignee: Unassigned
• Reporter: Weston Pace
• Created: 13/Apr/22 04:17
• Updated: 11/Jan/23 11:42

Description

Many of the ExecNode operations use thread local state (mostly temporary buffers) to avoid per-batch allocation. Currently we are using ThreadIndexer but to get the thread local state requires locking a mutex and a map lookup. For some of the critical sections we are developing in hash-join this has become a bottleneck. Ideally we can replace this with something that relies on thread local state instead of a map shared across all threads.

Sub-Tasks

• [C++] Add a ThreadLocalState concept built on thread local: Open
• [C++] Migrate existing usage of ThreadIndexer to ThreadLocalState and get rid of ThreadIndexer: Open