Pricing question


In provisioned capacity mode, does writing a single row per second with less than 1KB of data use an entire WCU?
More concretely, if I write 10 rows, each with 50 bytes, per second have I used an entire WCU even though only 500 bytes have been written? Or am I actually using 10 WCUs since I wrote 10 rows in a single second?

Similarly with RCUs, if I issue a query once per second that returns multiple rows, but with an aggregate size of less than 4KB is the entire RCU used?
Concretely, I issue a SELECT and get back 10 rows, each with 100 bytes of data I'm below the 4KB limit per RCU. If I then issue another SELECT within the same second, and get back another 1000 bytes of data have I used 2 RCUs, or 1 RCU since I've only read 2000 bytes in this second?

asked 4 years ago226 views
1 Answer

If you write 10 rows each with 50 bytes you will consume 10 WCU though you wrote only 500 bytes which is less the 1 KB WCU size. Even if you write these 10 rows in a batch you will consume 10 WCU.

On read side if aggregate size of your single query is less than 4 KB you will consume 1 RCU.
But your next query also will cost 1 RCU (your 2 queries cost 2 RCU) though aggregate size of two query result is still below 4 KB. Each transaction is charged individually.

answered 4 years ago

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