Hum, my bad. Thank you!
On Tue, Mar 19, 2013 at 11:55 PM, Wei Zhu <wz1...@yahoo.com> wrote: > There is setting in the cassandra.yaml file which controls that. > > > # Whether or not a snapshot is taken of the data before keyspace truncation > # or dropping of column families. The STRONGLY advised default of true > # should be used to provide data safety. If you set this flag to false, > you will > # lose data on truncation or drop. > auto_snapshot: true > > > ----- Original Message ----- > From: "Víctor Hugo Oliveira Molinar" <vhmoli...@gmail.com> > To: user@cassandra.apache.org > Sent: Tuesday, March 19, 2013 11:50:35 AM > Subject: Truncate behaviour > > Hello guys! > I'm researching the behaviour for truncate operations at cassandra. > > > Reading the oficial wiki page( http://wiki.apache.org/cassandra/API ) we > can understand it as: > > "Removes all the rows from the given column family." > > > And reading the DataStax page( > http://www.datastax.com/docs/1.0/references/cql/TRUNCATE ) we can > understand it as: > " A TRUNCATE statement results in the immediate, irreversible removal of > all data in the named column family." > > > But I think there is a missing and important point about truncate > operations. > At least at 1.2.0 version, whenever I run a truncate operation, C* > automatically creates a snapshot file of the column family, resulting in a > fake free disk space. > > I'm intentionally mentioning 'fake free disk space' because I only figured > it out when the machine disk space was at high usage. > > > > > - Is it a security C* behaviour of creating snapshots for each CF before > truncate operation? > - In my scenario I need to purge my column family data every day. > I thought that truncate could handle it based at the docs. But it doesnt. > And since I dont want to manually delete those snapshots, I'd like to know > if there is a safe and practical way to perform a daily purge of this CF > data. > > > > Thanks in advance! >
