= New Features

* A provenance dataset extension has been added. This extension makes
  SQL queries include a comment describing how the dataset was built.
  This can make debugging complex cases significantly easier. Here's
  a simple example:

    DB.extension :provenance

    DB[:table].
      select(:a).
      where{b > 10}.
      order(:c).
      limit(10)
      # SQL:
      # SELECT a FROM table WHERE (b > 10) ORDER BY c LIMIT 10 --
      #  -- Dataset Provenance
      #  -- Keys:[:from] Source:(eval at bin/sequel:257):2:in `<main>'
      #  -- Keys:[:select] Source:(eval at bin/sequel:257):3:in `<main>'
      #  -- Keys:[:where] Source:(eval at bin/sequel:257):4:in `<main>'
      #  -- Keys:[:order] Source:(eval at bin/sequel:257):5:in `<main>'
      #  -- Keys:[:limit] Source:(eval at bin/sequel:257):6:in `<main>'

  With the above example, it's obvious how the dataset is created, but
  but in real applications, where datasets can be built from multiple
  files, seeing where each dataset clone was made can be helpful.

  The source listed will skip locations in the Ruby standard library
  as well as Sequel itself.  Other locations can be skipped by
  providing a Database :provenance_caller_ignore Regexp option:

    DB.opts[:provenance_caller_ignore] = /\/gems\/library_name-/

= Other Improvements

* For dataset methods where Sequel can determine that the return
  value would be equivalent to the receiver, Sequel now returns the
  receiver.  This reduces the number of dataset allocations.

* Sequel now supports Dataset#skip_locked on MariaDB 10.6+.