# Considerations and limitations when using the Spark connector
Considerations
+ We suggest that you turn on SSL for the JDBC connection from Spark on Amazon EMR to Amazon Redshift.
+ We suggest that you manage the credentials for the Amazon Redshift cluster in Amazon Secrets Manager as a best practice. Refer to [Using Amazon Secrets Manager to retrieve credentials for connecting to Amazon Redshift](https://docs.amazonaws.cn/redshift/latest/mgmt/redshift-secrets-manager-integration.html) for an example.
+ We suggest that you pass an IAM role with the parameter `aws_iam_role` for the Amazon Redshift authentication parameter.
+ The parameter `tempformat` currently doesn't support the Parquet format.
+ The `tempdir` URI points to an Amazon S3 location. This temp directory isn't cleaned up automatically and therefore could add additional cost. 
+ Consider the following recommendations for Amazon Redshift:
  + We suggest that you block public access to the Amazon Redshift cluster.
  + We suggest that you turn on [Amazon Redshift audit logging](https://docs.amazonaws.cn/redshift/latest/mgmt/db-auditing.html).
  + We suggest that you turn on [Amazon Redshift at-rest encryption](https://docs.amazonaws.cn/redshift/latest/mgmt/security-server-side-encryption.html).
+ Consider the following recommendations for Amazon S3:
  + We suggest that you [block public access to Amazon S3 buckets](https://docs.amazonaws.cn/AmazonS3/latest/userguide/access-control-block-public-access.html).
  + We suggest that you use [Amazon S3 server-side encryption](https://docs.amazonaws.cn/AmazonS3/latest/userguide/serv-side-encryption.html) to encrypt the Amazon S3 buckets used.
  + We suggest that you use [Amazon S3 lifecycle policies](https://docs.amazonaws.cn/AmazonS3/latest/userguide/object-lifecycle-mgmt.html) to define the retention rules for the Amazon S3 bucket.
  + Amazon EMR always verifies code imported from open-source into the image. For security, we don't support the following authentication methods from Spark to Amazon S3:
    + Setting Amazon access keys in the `hadoop-env` configuration classification
    + Encoding Amazon access keys in the `tempdir` URI

For more information on using the connector and its supported parameters, see the following resources:
+ [Amazon Redshift integration for Apache Spark](https://docs.amazonaws.cn/redshift/latest/mgmt/spark-redshift-connector.html) in the *Amazon Redshift Management Guide*
+ The [`spark-redshift` community repository](https://github.com/spark-redshift-community/spark-redshift#readme) on Github