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From "Peter Bailis (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-7056) Add RAMP transactions
Date Wed, 25 Jun 2014 17:16:27 GMT


Peter Bailis commented on CASSANDRA-7056:

> RAMP has a requirement that anything being read/written that way is always written in
the same groupings. If you update B,C and then update A,B. You can't read B,C anymore successfully,
as the times on B and C will never match.

This isn't entirely correct. Let's say I do an atomic batch B1 that writes B = 1 and C = 1
with timestamp 1, then you do an atomic batch B2 that writes A = 2 and B = 2 at timestamp
2. Under RAMP, subsequent batch reads from B and C will return B = 2, C = 1. The timestamps
on B and C will indeed---as you point out---never match, but simply returning matching timestamps
is *not* not the goal: the goal is that if you read any write in a given batch, you will read
the rest of the writes in the batch (to the items you requested in the batch read)

> Add RAMP transactions
> ---------------------
>                 Key: CASSANDRA-7056
>                 URL:
>             Project: Cassandra
>          Issue Type: Wish
>          Components: Core
>            Reporter: Tupshin Harper
>            Priority: Minor
> We should take a look at [RAMP|]
transactions, and figure out if they can be used to provide more efficient LWT (or LWT-like)

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