WOS and ROS

[rexma]

WOS contained UnCommited data or Both?
Mergeout Happened only in ROS or ROS and Tuple mover?

[JimKnicely]

Hi,

WOS contained UnCommited data or Both?

The WOS can contain both committed and uncommitted data. Data is written to the ROS during a moveout which"flushes" all historical data from the WOS to the ROS. There are three parameters that control when this happens (MoveOutInterval, MoveOutMaxAgeTime and MoveOutSizePct).

Mergeout Happened only in ROS or ROS and Tuple mover?

The Tuple Mover is responsible for performing the Mergeout which is the process of consolidating ROS containers and purging deleted records.

I hope this helps!

[sarah]

Hi,

If the WOS contains committed data then what happens when the node crashes? Will I lose the committed information?!?! That seems dangerous!

[JimKnicely]

Sarah,

Data in the WOS is distributed across the cluster nodes via buddy projections! So if one node fails, its in-memory data will be safely available in one of your other nodes This is one of the reasons Vertica is said to be "Highly Available"!

[vicky]

Can someone explain me whether the projections exist physically or not and if they exist why are they not stored in containers if unpartitioned .Why are only partitioned projections stored in the containers ??And what is ros_id ??Does it indicate the container?? I am totally confused ...Answer would be highly appreciated...!!!Thankyou