Module: PgHero::Methods::Explain

Included in:
Database
Defined in:
lib/pghero/methods/explain.rb

Instance Method Summary collapse

Instance Method Details

#explain(sql, analyze: nil, verbose: nil, costs: nil, settings: nil, generic_plan: nil, buffers: nil, wal: nil, timing: nil, summary: nil, format: "text") ⇒ Object

note: this method is not affected by the explain option



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# File 'lib/pghero/methods/explain.rb', line 5

def explain(sql, analyze: nil, verbose: nil, costs: nil, settings: nil, generic_plan: nil, buffers: nil, wal: nil, timing: nil, summary: nil, format: "text")
  options = []
  add_explain_option(options, "ANALYZE", analyze)
  add_explain_option(options, "VERBOSE", verbose)
  add_explain_option(options, "SETTINGS", settings)
  add_explain_option(options, "GENERIC_PLAN", generic_plan)
  add_explain_option(options, "COSTS", costs)
  add_explain_option(options, "BUFFERS", buffers)
  add_explain_option(options, "WAL", wal)
  add_explain_option(options, "TIMING", timing)
  add_explain_option(options, "SUMMARY", summary)
  options << "FORMAT #{explain_format(format)}"

  sql = "(#{options.join(", ")}) #{sql}"
  explanation = nil

  # use transaction for safety
  with_transaction(statement_timeout: (explain_timeout_sec * 1000).round, rollback: true) do
    if (sql.delete_suffix(";").include?(";") || sql.upcase.include?("COMMIT")) && !explain_safe?
      raise ActiveRecord::StatementInvalid, "Unsafe statement"
    end
    explanation = execute("EXPLAIN #{sql}").map { |v| v["QUERY PLAN"] }.join("\n")
  end

  explanation
end