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Why ADD clicks instead of read-modify-write?

What is a VPC: your own private network inside one AWS Region, example ThreeTierVpc 10.0.0.0/16.

Why ADD clicks instead of read-modify-write? Two redirects at once can both read clicks=5 and both write 6 — one click lost. UpdateItem ADD is atomic on the server for that attribute. UpdateExpression SET … ADD clicks :one with :one = 1 on every redirect. — Why ADD clicks instead of read-modify-write? · Download PNG

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What this card says

What it is

Two redirects at once can both read clicks=5 and both write 6 — one click lost.

Why it matters

UpdateItem ADD is atomic on the server for that attribute.

How / example

UpdateExpression SET … ADD clicks :one with :one = 1 on every redirect.

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