Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Configure pre-warming for tables in Amazon Keyspaces

Amazon Keyspaces automatically scales storage partitions based on on-demand or provisioned throughput, but for new tables or sudden throughput peaks, it can take longer to allocate the required storage partitions. To insure that a new or existing table has enough capacity to support anticipated peak throughput, you can manually set specific warm throughput values to pre-warm your table.

Warm throughput refers to the number of read and write operations your Amazon Keyspaces table can instantaneously support. These values are available by default for all new and existing tables. If you are using on-demand mode, or if you update your provisioned throughput, Amazon Keyspaces ensures that your application is able to issue requests up to those values instantly.

Amazon Keyspaces automatically adjusts warm throughput values as your usage increases. To adjust throughput capacity for upcoming peak events, for example when you're migrating data from another database, which may require loading terabytes of data in a short period of time, you can manually increase your tables warm throughput values. This is useful for planned peak events where request rates might increase by 10x, 100x, or more. First, assess whether the current warm throughput is sufficient to handle the expected traffic. Then, if you need to pre-warm the table for the planned peak workload, you can increase the warm throughput value manually without changing your throughput settings or capacity mode.

You can pre-warm tables for read operations, write operations, or both. You can increase this value for new and existing single-Region tables and multi-Region tables and the warm throughput settings you set apply automatically to all replicas of the multi-Region tables. There is no limit to the number of Amazon Keyspaces tables you can pre-warm at any time. The time to complete pre-warming depends on the values you set and the size of the table. You can submit simultaneous pre-warm requests and these requests don't interfere with any table operations. You can pre-warm your table up to the table quota limit for your account in that Region. Use the Service Quotas console to check your current quotas and increase them if needed.

The warm throughput values that Amazon Keyspaces adjusts based on your on-demand usage or provisioned capacity are available by default for all tables without additional charges. However, if you manually increase the default warm throughput values to pre-warm tables for peak traffic events, additional charges apply. For more information, see Amazon Keyspaces pricing.

Here are some different scenarios and best practices you might consider when pre-warming Amazon Keyspaces tables.

Warm throughput and uneven access patterns

A table might have a warm throughput of 30,000 read units per second and 10,000 write units per second, but you could still experience capacity exceeded events on reads or writes before hitting those values. This is likely due to a hot partition. While Amazon Keyspaces can keep scaling to support virtually unlimited throughput, each individual partition is limited to 1,000 write units per second and 3,000 read units per second. If your application drives too much traffic to a small portion of the table’s partitions, capacity exceeded events can occur even before you reach the table's warm throughput values. We recommend following Amazon Keyspaces best practices to ensure seamless scalability and avoid hot partitions.

Warm throughput for a provisioned table

Consider a provisioned table that has a warm throughput of 30,000 read units per second and 10,000 write units per second but currently has a provisioned throughput of 4,000 RCUs and 8,000 WCUs. You can instantly scale the table's provisioned throughput up to 30,000 RCUs or 10,000 WCUs by updating your provisioned throughput settings. As you increase the provisioned throughput beyond these values, the warm throughput adjusts automatically to the new higher values, because you have established a new peak throughput. For example, if you set the provisioned throughput to 50,000 RCU, the warm throughput increases to 50,000 read units per second.

"ProvisionedThroughput": 
    {
        "ReadCapacityUnits": 4000,
        "WriteCapacityUnits": 8000 
    }
"WarmThroughput": 
    { 
        "ReadUnitsPerSecond": 30000,
        "WriteUnitsPerSecond": 10000
    }

Warm throughput for an on-demand table

A new on-demand table starts with a warm throughput of 12,000 read units per second and 4,000 write units per second. Your table can instantly accommodate sustained traffic up to these levels. When your requests exceed 12,000 read units per second or 4,000 write units per second, the warm throughput adjusts automatically to the higher values.

"WarmThroughput": 
    { 
        "ReadUnitsPerSecond": 12000,
        "WriteUnitsPerSecond": 4000
    }

Best practices for pre-warming Amazon Keyspaces tables

Follow these best practices when implementing pre-warming for your Amazon Keyspaces tables: