Long running transactions interfere with vacuuming and increase contention for locks. Everything depends on your workload but a long running transactions holding an important lock is an easy way to bring down production.
> The AmazonDynamoDBLockClient is a general purpose distributed locking library built on top of DynamoDB. It supports both coarse-grained and fine-grained locking.
If the system is already using SQS, DynamoDB has this locking library which is lighter weight for this use case
https://github.com/awslabs/amazon-dynamodb-lock-client
> The AmazonDynamoDBLockClient is a general purpose distributed locking library built on top of DynamoDB. It supports both coarse-grained and fine-grained locking.