Class: ActiveRecord::ConnectionAdapters::PostgreSQL::ExplainPrettyPrinter
Do not use. This class is for internal use only.
Relationships & Source Files | |
Inherits: | Object |
Defined in: | activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb |
Instance Method Summary
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#pp(result)
Pretty prints the result of an EXPLAIN in a way that resembles the output of the
::ActiveRecord::ConnectionAdapters::PostgreSQL
shell:
Instance Method Details
#pp(result)
Pretty prints the result of an EXPLAIN in a way that resembles the output of the ::ActiveRecord::ConnectionAdapters::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/explain_pretty_printer.rb', line 20
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