Implement index report functions

[noahshaw11]

Overview

Implement index report functions to facilitate memory leak detections.

Testing recommendations

Related Issues or Pull Requests

Checklist

• Code is written and works correctly
• Changes are covered by tests
• Any new configurable parameters are documented in rel/overlay/etc/default.ini
• A PR for documentation changes has been made in https://github.com/apache/couchdb-documentation

[noahshaw11]

I also want to clarify the need for a print_report function on top of the existing print_table function. If the print_table function is used, the following is printed:

> couch_mrview_debug:view_report().
|                       info                       |                                                                                           signature
|                     signature                    |                                                                    39b98489b79419503499bbee402040c7
|                       info                       |                                                                                             db_name
|                      db_name                     |                                                            shards/00000000-ffffffff/dbv1.1654270700
|                       info                       |                                                                                            idx_name
|                      idx_name                    |                                                                                    _design/dbv1ddoc
|                       info                       |                                                                                         reduce_funs
|                    reduce_funs                   |
|                       info                       |                                                                                                 def
|                        def                       |                                                                     function(doc){emit(doc.id, 1);}
|                       info                       |                                                                                          update_seq
|                     update_seq                   |                                                                                                   3
|                       info                       |                                                                                           purge_seq
|                     purge_seq                    |                                                                                                   0
|                       info                       |                                                                                      view_file_path
|                   view_file_path                 |1/data/.shards/00000000-ffffffff/dbv1.1654270700_design/mrview/39b98489b79419503499bbee402040c7.view
|                       info                       |                                                                                     pending_updates
|                  pending_updates                 |                                                                                                   0
[ok,ok,ok,ok,ok,ok,ok,ok,ok]

On the other hand, if print_report is used, the following is printed:

> couch_mrview_debug:view_report().
|                       info                       |                                                                                               value
|                     signature                    |                                                                    39b98489b79419503499bbee402040c7
|                      db_name                     |                                                            shards/00000000-ffffffff/dbv1.1654270218
|                      idx_name                    |                                                                                    _design/dbv1ddoc
|                    reduce_funs                   |
|                        def                       |                                                                     function(doc){emit(doc.id, 1);}
|                     update_seq                   |                                                                                                   3
|                     purge_seq                    |                                                                                                   0
|                   view_file_path                 |1/data/.shards/00000000-ffffffff/dbv1.1654270218_design/mrview/39b98489b79419503499bbee402040c7.view
|                  pending_updates                 |                                                                                                   0
[ok,ok,ok,ok,ok,ok,ok,ok,ok]

Also, I think it would be a good idea to truncate the view_file_path in some form.

[iilyak]

Looks really good. Just a few small improvements left. Mostly in documentation.

[iilyak]

+1, Good work.

[noahshaw11]

+1, Good work.

Thanks, @iilyak!