Those are for "majority of replicas in a single datacenter." The code isn't quite finished.
2010/3/22 Patricio Echagüe <patric...@gmail.com> > Hi all, is there any documentation for: > > ConsistencyLevel.DCQUORUM and ConsistencyLevel.DCQUORUMSYNC ? > > DC = Data Center ? > > Thanks > > > On Thu, Feb 25, 2010 at 12:12 PM, Masood Mortazavi < > masoodmortaz...@gmail.com> wrote: > >> From the code, it appears that for "get" the default is ONE. >> Column column = thriftClient_.get(tableName, key, path, >> ConsistencyLevel.ONE).column >> - m. >> >> >> On Thu, Feb 25, 2010 at 11:08 AM, Masood Mortazavi < >> masoodmortaz...@gmail.com> wrote: >> >>> >>> >>> What is the write and read consistency level for the CLI tool >>> "cassandra-cli" ? >>> >>> Do the "set" and "get" commands in the "cli" allow the Consistency Level >>> to be specified for a given "set" or "get"? >>> >>> Is there a current specification of CLI anywhere on the wiki? >>> >>> ( How are JIRA's related to the CLI tagged in the JIRA system assuming >>> they are "tagged" separately? In other words, is there an identifier for >>> them? ) >>> >>> Regards, >>> m. >>> >>> ========================== >>> The Cassandra "API" describes write and read consistency levels as >>> follows: >>> http://wiki.apache.org/cassandra/API >>> Write >>> >>> *Level* >>> >>> *Behavior* >>> >>> ZERO >>> >>> Ensure nothing. A write happens asynchronously in background >>> >>> ANY >>> >>> (Coming in 0.6) Ensure that the write has been written to at least 1 >>> node, including hinted recipients. >>> >>> ONE >>> >>> Ensure that the write has been written to at least 1 node's commit log >>> and memory table before responding to the client. >>> >>> QUORUM >>> >>> Ensure that the write has been written to <ReplicationFactor> / 2 + 1nodes >>> before responding to the client. >>> >>> ALL >>> >>> Ensure that the write is written to all <ReplicationFactor> nodes before >>> responding to the client. Any unresponsive nodes will fail the operation. >>> >>> Read >>> >>> *Level* >>> >>> *Behavior* >>> >>> ZERO >>> >>> Not supported, because it doesn't make sense. >>> >>> ANY >>> >>> Not supported. You probably want ONE instead. >>> >>> ONE >>> >>> Will return the record returned by the first node to respond. A >>> consistency check is always done in a background thread to fix any >>> consistency issues when ConsistencyLevel.ONE is used. This means >>> subsequent calls will have correct data even if the initial read gets an >>> older value. (This is called read repair.) >>> >>> QUORUM >>> >>> Will query all storage nodes and return the record with the most recent >>> timestamp once it has at least a majority of replicas reported. Again, the >>> remaining replicas will be checked in the background. >>> >>> ALL >>> >>> Will query all storage nodes and return the record with the most recent >>> timestamp once all nodes have replied. Any unresponsive nodes will fail the >>> operatio >>> >>> >> > > > -- > Patricio.- >
