cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Victor Kabdebon <victor.kabde...@gmail.com>
Subject Re: Appending to fields
Date Tue, 31 May 2011 20:57:23 GMT
As Jonathan stated I believe that the insert is in O(N + M), unless there
are some operations that I don't know.

There are other NoSQL database that  can be used with Cassandra as "buffers"
for quick access and modification and then after the content can be dumped
into Cassandra for long term storage. Here is an example with Redis :

http://redis.io/commands/append
The "append" command is said to be in O(1) but it is a little bit suspicious
to me...

Best regards,
Victor Kabdebon
http://www.voxnucleus.fr

2011/5/31 Jonathan Ellis <jbellis@gmail.com>

> On Tue, May 31, 2011 at 2:22 PM, Marcus Bointon
> <marcus@synchromedia.co.uk> wrote:
> > mysql reads the entire value of y, appends the data, then writes the
> whole thing back, which unfortunately is an O(n^2) operation.
>
> Actually, this analysis is incorrect. Appending M bytes to N is O(N +
> M) which isn't the same as N^2 at all.
>
> At least in Cassandra, nor can I think of any possible algorithm which
> would allow MySQL to achieve N^2, but I don't claim to be an expert
> there.
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>

Mime
View raw message