Thanks Edmond for your answer.
I added this to the FAQ http://wiki.apache.org/cassandra/FAQ
as even google does not seem to know anything about "Sorted Strings Table"
http://www.google.com/search?q=%22Sorted+Strings+Table%22 ;)
Alex
Edmond Lau wrote:
On Fri, Nov 13, 2009 at 12:20 AM, TuxRacer69 <[email protected]> wrote:
Hello Cassandra Users!
On the wiki page:
http://wiki.apache.org/cassandra/ArticlesAndPresentations
there is a link to J. Ellis pdf:
http://assets.en.oreilly.com/1/event/27/Cassandra_%20Open%20Source%20Bigtable%20+%20Dynamo%20Presentation.pdf
At page 41 we have: (Roadmap) Cassandra 0.5
Cassandra 0.5
Millions of columns per row
This will require another data format change
Question 1:
-----------------
Is there any Jira logged for this change yet?
I'd like to understand
a) if a full data rebuild will be necessary for upgrading from 0.4.X to 0.5
b) what the limitations currently are in Cassandra.
- How many keys per column family
- How many columns per key in a standard column family
- How many columns per key in a super column family, and how many subcolumns
within a supercolumn key
Page http://wiki.apache.org/cassandra/CassandraLimitations
says "The main limitation on column and supercolumn size is that all data
for a single key and column must fit (on disk) on a single machine in the
cluster." but that does not really answer the questions above (as know we
can have 1Tb disk cheaply)
Question 2:
----------------
Page 15 and 16: Architecture layer.
How could we defined Memtables and SStables? What the two 'S' stand for in
SSTable?
A Memtable is Cassandra's in-memory representation of key/value pairs
before the data gets flushed to disk as an SSTable. An SSTable
(terminology borrowed from Google) stands for Sorted Strings Table and
is a file of key/value string pairs, sorted by keys.
Edmond
Thanks a lot
Alex
