Write multiple hash field across different keys atomically

[Boyang Chen]

Hey there,

I'm new to Redis, and we have a use case to write multiple hash fields in an atomic manner, is that something Redis could add support for? To be specific, hmset doesn't help because I'm trying to write:
key A, field x

key B, field y

atomically, not key A, field (x, y)

I know there is transaction support in Redis, but since we don't need RMW, so probably worth getting a standalone API. Let me know what you think.

[Viktor Söderqvist]

MULTI
HSET A x hello
HSET B y world
EXEC

The commands can be sent in a pipeline so there is no extra
round-trip. Multi-exec is very fast. It simply queues up the
queries and executes them together.

I think it's very unlikely that Redis will add special command to
write to multiple keys simultaneously.

Cheers,
Viktor

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[Boyang Chen]

Thanks, however I don’t think pipeline will have any transactional guarantee?

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[Viktor Söderqvist]

Pipeline has nothing to do with transactions.

Pipeline just means that you send multiple commands without waiting for
the reply for the previous commands.

MULTI-(commands)-EXEC is a transaction. You can send one command and
wait for reply before you send the next command, or you can send all
commands at once in a pipeline.

Only HSET a x hello; HSET b y world in a pipeline (without MULTI) is not
a transaction.

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