public String getPerformanceInsightsKMSKeyId() {
        return this.performanceInsightsKMSKeyId;
    }
<p>
The KMS key identifier for encryption of Performance Insights data.
</p>
<p>
The KMS key identifier is the key ARN, key ID, alias ARN, or alias name for the KMS key.
</p>
<p>
If you do not specify a value for PerformanceInsightsKMSKeyId, then Amazon DocumentDB uses your default KMS key.
There is a default KMS key for your Amazon Web Services account. Your Amazon Web Services account has a different
default KMS key for each Amazon Web Services region.
</p>

@return The KMS key identifier for encryption of Performance Insights data.</p>
        <p>
        The KMS key identifier is the key ARN, key ID, alias ARN, or alias name for the KMS key.
        </p>
        <p>
        If you do not specify a value for PerformanceInsightsKMSKeyId, then Amazon DocumentDB uses your default
        KMS key. There is a default KMS key for your Amazon Web Services account. Your Amazon Web Services
        account has a different default KMS key for each Amazon Web Services region.
aws-java-sdk-docdb/src/main/java/com/amazonaws/services/docdb/model/ModifyDBInstanceRequest.java