When `acts-as-taggable-on`'s `.tagged_with()` is used with `any: true`,
the gem will use `SELECT *` regardless of any previous (or following) requests
of selecting a limited amount of columns.
Given that the `articles` table has [73 columns](https://dev.to/admin/blazer/queries/314-number-of-columns-in-all-tables)
that will amount to wasted RAM memory for columns we don't need.
By "unscoping" any previous `select()` we can optimize used memory.
Before:
```ruby
[24] pry(main)> Article.tagged_with([:ruby], any: true).select(:id, :name).to_sql
=> "SELECT \"articles\".*, \"articles\".\"id\", \"name\" FROM \"articles\" WHERE EXISTS (SELECT * FROM \"taggings\" WHERE \"taggings\".\"taggable_id\" = \"articles\".\"id\" AND \"taggings\".\"taggable_type\" = 'Article' AND \"taggings\".\"tag_id\" IN (SELECT \"tags\".\"id\" FROM \"tags\" WHERE (\"tags\".\"name\" LIKE 'ruby' ESCAPE '!')))"
```
Note, how the SQL query is `articles.*, articles.column_a`
After:
[25] pry(main)> Article.tagged_with([:ruby], any: true).unscope(:select).select(:id, :name).to_sql
=> "SELECT \"articles\".\"id\", \"name\" FROM \"articles\" WHERE EXISTS (SELECT * FROM \"taggings\" WHERE \"taggings\".\"taggable_id\" = \"articles\".\"id\" AND \"taggings\".\"taggable_type\" = 'Article' AND \"taggings\".\"tag_id\" IN (SELECT \"tags\".\"id\" FROM \"tags\" WHERE (\"tags\".\"name\" LIKE 'ruby' ESCAPE '!')))"
```
`articles.*` is gone :-)
- https://github.com/mbleigh/acts-as-taggable-on/issues/936
- 47da5036de/lib/acts_as_taggable_on/taggable/tagged_with_query/any_tags_query.rb (L2-L8)
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