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From Edward Capriolo <>
Subject Re: Schema size
Date Fri, 25 May 2012 15:21:13 GMT
In Cassandra 1.1 the schema is no longer a full migration history.
Before that each schema change is recorded in the table and they all
have to be replayed when a node bootstraps. Also 1.1 has some bug ATM
that means you should not switch to it.

People tend to say things like "with cassandra X you now can have more
CF and KS's" but back in the day the thinking was "You only need 1"

Hector has a concept of "virtual keyspaces" which is a model that is
likely to give you more success then 1500 CFs. I am not a fan of
dynamically creating and tearing down CFS on the fly or 1 per customer

When the wrinkles come out of 1.1 and up upgrade the schema size
should shrink down.

On Fri, May 25, 2012 at 6:25 AM, Sasha Yanushkevich <> wrote:
> Hi All,
> I have a question about schema cleaning in cassandra.
> I use cassandra version 1.0.9. I have 5 keyspaces and about 1500 column
> family per keyspace. After dynamically creating and deleting CF my schema's
> sstables  size were very high. For example size of Migrations was 45 GB and
> Schema sstable size was 45 GB whereas all data size was about 10 GB.
> Why schema grow was so fast? And how may I cleanup schema or later schema
> cleanup itself?
> --
> Best regards,
> Alexander

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