method

pp

v4.2.7 - Show latest stable - Class: ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements::ExplainPrettyPrinter

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)

# 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

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