Boto3 rds-data continueAfterTimeout not supported in Aurora Serverless?

Question

I am trying to use AWS rds-data api to perform some heavy etl in aurora Serverless Postgresql.

As per AWS Rds DATA documentation, By default, a call times out if it's not finished processing within 45 seconds. However, you can continue running a SQL statement if the call times out by using the continueAfterTimeout parameter.

I see that boto3 rds-data supports the continueAfterTimeout parameter (a boolean). And I can use this flag in a transaction like this.

def execute_transaction_query(sql,  transaction_id):
        print(sql)
        response = rds_client.execute_statement(
            secretArn=AURORA_DB_CREDS_ARN,
            resourceArn=AURORA_DB_ARN,
            database=AURORA_DB_NAME,
            sql=sql,
            transactionId=transaction_id,
            continueAfterTimeout=True, # boolean flag to continue after timeout in theory
        )

However, the queries are still failling after 45 seconds with the error

An error occurred (StatementTimeoutException) when calling the ExecuteStatement operation: Request timed out

Answer 1

Ok so the reason rds-data calls fail is that the continueAfterTimeout=True doesnt mean the boto3 call wont fail, just that the sql query running on the database will continue running.

So what you need to do when running rds-data etls is to execute statements in a try/catch block:

            response = rds_client.execute_statement(
                secretArn=AURORA_DB_CREDS_ARN,
                resourceArn=AURORA_DB_ARN,
                database=AURORA_DB_NAME,
                sql=sql,
                transactionId=transaction_id,
                continueAfterTimeout=True,
            )
        except botocore.exceptions.ClientError as error:
            # aurora fails automatically after 45 seconds but continues in the db
            #https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/data-api.html
            if error.response['Error']['Code'] == 'StatementTimeoutException':
                print('QUERY TIMEDOUT AFTER MAX 45 SECONDS. THIS IS FINE')
                # arbitrary wait in case the commit transaction fails with timeout
                time.sleep(60)
            else:
                raise Exception(error)