In the previous chapter, we talked about the best practices one should follow in order to get the most out of DynamoDB. In this chapter, we are going to talk about some advanced topics:
Monitoring DynamoDB tables
AWS authentication service
AWS IAM integration with DynamoDB
Security token service
Error handling in DynamoDB
We will also talk about limitations of DynamoDB that every developer needs to consider while designing the schema and doing the implementation.
To start with, let's get familiar with AWS CloudWatch, which is a network-monitoring service offered by Amazon Web Service. While creating a table, you can set alarms for various events such as provisioning a throughput with exceeded exceptions, maintaining certain threshold, and so on. A table's size in terms of bytes or number of items is not available as a CloudWatch metric by default; however, this can be set up using the DescribeTable operation, and it is a good practice to keep watch on this metric. These metrics are very important from the database admin's point of view, but as we are using a hosted service here, we need not hire a DBA specialist. These metrics would help us keep track of whether there is any sudden demand of resources happening or not, and if the peak and slow time frames can be drawn for our application so that we can keep more read and write throughput for peak time frames and lesser throughput for slow time frames. CloudWatch gives us...
Some of you might be aware of the concept called access control on resources. This is a very familiar concept in relational databases where we can have multiple users accessing the same database but different roles. This is very crucial from the application's security point of view. A user should have privileges and access to only the required resources in order to avoid misuse. In order to implement the concept on Cloud, AWS supports Identity and Access Management (IAM) as a service. This service allows us to perform the following:
Create multiple AWS accounts that access the same resources with different privileges
Create group users with similar privileges for the same level of accesses
Create separate user credentials for each user and maintain privacy
Provide fine-grained control on shared resources
Get a collective bill for all the users under one account
We can use IAM to control DynamoDB resources and API accesses to users. To do so, you...
In this section, we will try to list the limitations put by AWS on DynamoDB operations. These limits need to be considered while using DynamoDB in order to keep your application 100 percent available without any hiccups.
|
Attribute |
Limitation Details |
|---|---|
|
Table name/index name |
Table/index name can contain A-Z, a-z, 0-9, underscore (_), dash (-) and dot (.). The table name should be a minimum of 3 and maximum of 255 characters. There is no limit on the table name that starts with the previously mentioned special characters. |
|
Tables per account |
You can create a maximum of 256 tables per region through one account. |
|
Table size |
There is no limit on the number of items or size of the table in terms of bytes. |
|
Hash key |
There is no limit on the number of hash keys in a table. |
|
Range key |
There is no limit on the number of range keys per unique hash key for tables without a local secondary index. For a table with a local secondary index, the total size of the table, including... |
