method

pp

v4.1.8 - Show latest stable - 0 notes - Class: ExplainPrettyPrinter

1.0.0
1.1.6
1.2.6
2.0.3
2.1.0
2.2.1
2.3.8
3.0.0
3.0.9
3.1.0
3.2.1
3.2.8
3.2.13
4.0.2 (0)
4.1.8 (0)
4.2.1
4.2.7
4.2.9
5.0.0.1
5.1.7
5.2.3
6.0.0
6.1.3.1
6.1.7.7
7.0.0
7.1.3.2
What's this?

pp(result) public

Pretty prints the result of a EXPLAIN in a way that resembles the output of the PostgreSQL shell:

                                  QUERY PLAN
------------------------------------------------------------------------------
 Nested Loop Left Join  (cost=0.00..37.24 rows=8 width=0)
   Join Filter: (posts.user_id = users.id)
   ->  Index Scan using users_pkey on users  (cost=0.00..8.27 rows=1 width=4)
         Index Cond: (id = 1)
   ->  Seq Scan on posts  (cost=0.00..28.88 rows=8 width=4)
         Filter: (posts.user_id = 1)
(6 rows)

Show source

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 24
          def pp(result)
            header = result.columns.first
            lines  = result.rows.map(&:first)

            # We add 2 because there's one char of padding at both sides, note
            # the extra hyphens in the example above.
            width = [header, *lines].map(&:length).max + 2

            pp = []

            pp << header.center(width).rstrip
            pp << '-' * width

            pp += lines.map {|line| " #{line}"}

            nrows = result.rows.length
            rows_label = nrows == 1 ? 'row' : 'rows'
            pp << "(#{nrows} #{rows_label})"

            pp.join("\n") + "\n"
          end

pp

Related methods

Flowdock - Team Inbox With Chat