Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for 
change notification.

The "ArchitectureOverview" page has been changed by StuHood.
The comment on this change is: Without an explanation for where the numbers 
came from, this blurb is useless..
http://wiki.apache.org/cassandra/ArchitectureOverview?action=diff&rev1=8&rev2=9

--------------------------------------------------

  
  You get consistency if R + W > N, where R is the number of records to read, W 
is the number of records to write, and N is the replication factor.  A 
ConsistencyLevel of ONE means R or W is 1.  A ConsistencyLevel of QUORUM means 
R or W is ceiling((N+1)/2).  A ConsistencyLevel of ALL means R or W is N.  So 
if you want to write with a ConsistencyLevel of ONE and then get the same data 
when you read, you need to read with ConsistencyLevel ALL.
  
- Cassandra vs MySQL with 50GB of data
- 
- 
- || MySQL       || Cassandra    ||
- ||~300ms write || ~0.12ms write||
- ||~350ms read  || ~15ms read   ||
- 

Reply via email to