> High read/write and low-ish size. Also it's faster

You posted a vague and meaningless assertion. If you do not have latency numbers and cost differences, you have absolutely nothing to show for, and you failed to provide any rationale that justified even whether any cache is required at all.

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odie5533 5 hours ago | parent [-]

At 10k RPS you'll see a significant cost savings with Redis over DynamoDB.

ElastiCache Serverless (Redis/Memcached): Typical latency is 300–500 microseconds (sub-millisecond response)

DynamoDB On-Demand: Typical latency is single-digit milliseconds (usually between 1–10 milliseconds for standard requests)

	▲	hvb2 an hour ago \| parent \| next [-]
		> At 10k RPS You would've used local memory first. At which point I cannot see getting to those request levels anymore > ElastiCache Serverless (Redis/Memcached): Typical latency is 300–500 microseconds (sub-millisecond response) Sure > DynamoDB On-Demand: Typical latency is single-digit milliseconds (usually between 1–10 milliseconds for standard requests) I know very little use cases where that difference is meaningful. Unless you have to do this many times sequentially in which case optimizing that would be much more interesting than a single read being .5 ms versus the typical 3 to 4 for dynamo (that last number is based on experience)
	▲	motorest 4 hours ago \| parent \| prev [-]
		> At 10k RPS you'll see a significant cost savings with Redis over DynamoDB. You need to be more specific than that. Depending on your read/write patterns and how much memory you need to allocate to Redis, back of the napkin calculations still point to the fact that Redis can still cost >$1k/month more than DynamoDB. Did you actually do the math on what it costs to run Redis?