[jira] [Created] (ARROW-12873) [C++][Compute] Support tagging ExecBatches with arbitrary extra information

["Ben Kietzman (Jira)" <ji...@apache.org>]

Ben Kietzman created ARROW-12873:
------------------------------------

             Summary: [C++][Compute] Support tagging ExecBatches with arbitrary extra information
                 Key: ARROW-12873
                 URL: https://issues.apache.org/jira/browse/ARROW-12873
             Project: Apache Arrow
          Issue Type: Improvement
          Components: C++
            Reporter: Ben Kietzman


Ideally, ExecBatches could be tagged with arbitrary optional objects for tracing purposes and to transmit execution hints from one ExecNode to another.

These should *not* be explicit members like ExecBatch::selection_vector is, since they may not originate from the arrow library. For an example within the arrow project: {{libarrow_dataset}} will be used to produce ScanNodes and a WriteNodes and it's useful to tag scanned batches with their {{Fragment}} of origin. However adding {{ExecBatch::fragment}} would result in a cyclic dependency.

To facilitate this tagging capability, we would need a type erased container something like
{code}
struct AnySet {
  void* Get(tag_t tag);
  void Set(tag_t tag, void* value, FnOnce<void(void*)> destructor);
};
{code}





--
This message was sent by Atlassian Jira
(v8.3.4#803005)