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Contents
# frozen_string_literal: true
module ROM
module Plugins
module Relation
module SQL
module Postgres
# PG-specific extensions which adds `Relation#explain` method
#
# @api public
module Explain
# Show the execution plan
# One of four different output formats are supported: plain text, XML, JSON, YAML
# JSON format will be parsed and unwrapped automatically, plan in other formats
# will be returned as a plain string.
# Other options will be transparently added to the statement.
#
# @example
# users.by_pk(1).explain(analyze: true, timing: false) # => Plan output
#
# @option :format [Symbol] Plan output format
#
# @return [Hash,String]
#
# @see https://www.postgresql.org/docs/current/static/sql-explain.html PostgreSQL docs
#
# @api public
def explain(format: :text, **options)
bool_options = options.map { |opt, value| "#{opt.to_s.upcase} #{!!value}" }
format_option = "FORMAT #{format.to_s.upcase}"
explain_value = [format_option, *bool_options].join(', ')
query = "EXPLAIN (#{explain_value}) #{dataset.sql}"
rows = dataset.with_sql(query).map(:'QUERY PLAN')
case format
when :json
rows[0][0]['Plan']
else
rows.join("\n")
end
end
end
end
end
end
end
end
ROM.plugins do
adapter :sql do
register :pg_explain, ROM::Plugins::Relation::SQL::Postgres::Explain, type: :relation
end
end
Version data entries
12 entries across 12 versions & 1 rubygems