Module: AppMap::Handler::Rails::SQLHandler::SQLExaminer

Defined in:
lib/appmap/handler/rails/sql_handler.rb

Defined Under Namespace

Classes: ActiveRecordExaminer, SequelExaminer

Class Method Summary collapse

Class Method Details

.examine(payload, sql:) ⇒ Object 



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# File 'lib/appmap/handler/rails/sql_handler.rb', line 46

def examine(payload, sql:)
  return unless (examiner = build_examiner)

  in_transaction = examiner.in_transaction?

  if AppMap.explain_queries? && examiner.database_type == :postgres
    if sql =~ /\A(SELECT|INSERT|UPDATE|DELETE|WITH)/i
      savepoint_established = \
        begin
          tx_query = in_transaction ? 'SAVEPOINT appmap_sql_examiner' : 'BEGIN TRANSACTION'
          examiner.execute_query tx_query
          true
        rescue
          # Probably: Sequel::DatabaseError: PG::InFailedSqlTransaction
          warn $!
          false
        end

      if savepoint_established
        plan = nil
        begin
          plan = examiner.execute_query(%(EXPLAIN #{sql}))
          payload[:query_plan] = plan.map { |line| line[:'QUERY PLAN'] }.join("\n")
        rescue
          warn "(appmap) Error explaining query: #{$!}"
        ensure
          tx_query = in_transaction ? 'ROLLBACK TO SAVEPOINT appmap_sql_examiner' : 'ROLLBACK'
          examiner.execute_query tx_query
        end
      end
    end
  end

  payload[:database_type] = examiner.database_type.to_s
end