# File activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb, line 37
def build_explain_clause(options = [])
  return "EXPLAIN" if options.empty?

  options = options.flat_map do |option|
    option.is_a?(Hash) ? option.to_a.map { |nested| nested.join("=") } : option
  end

  explain_clause = "EXPLAIN #{options.join(" ").upcase}"

  if analyze_without_explain? && explain_clause.include?("ANALYZE")
    explain_clause.sub("EXPLAIN ", "")
  else
    explain_clause
  end
end

# File activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb, line 27
def explain(arel_or_sql, binds = [], options = [])
  sql, binds = to_sql_and_binds(arel_or_sql, binds)
  sql = build_explain_clause(options) + " " + sql
  start   = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  result  = select_all(sql, "EXPLAIN", binds)
  elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start

  MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
end

# File activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb, line 23
def high_precision_current_timestamp
  HIGH_PRECISION_CURRENT_TIMESTAMP
end