Module: PgHero::Methods::Explain

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

Instance Method Summary collapse

Instance Method Details

#explain(sql) ⇒ Object 



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# File 'lib/pghero/methods/explain.rb', line 4

def explain(sql)
  sql = squish(sql)
  explanation = nil
  explain_safe = explain_safe?

  # use transaction for safety
  connection_model.transaction do
    # protect the DB with a 10 second timeout
    # this could potentially increase the timeout, but 10 seconds should be okay
    select_all("SET LOCAL statement_timeout = 10000")
    if (sql.sub(/;\z/, "").include?(";") || sql.upcase.include?("COMMIT")) && !explain_safe
      raise ActiveRecord::StatementInvalid, "Unsafe statement"
    end
    explanation = select_all("EXPLAIN #{sql}").map { |v| v["QUERY PLAN"] }.join("\n")
    raise ActiveRecord::Rollback
  end

  explanation
end