Other AWS Applications and Technologies Flashcards
Under what circumstances would you use AWS Simple Workflow Service over AWS step functions?
AWS SWF is only recommended for when you have external signals interacting in the process, or you need a child function to return a value to a parent process.
In RedShift, what is the purpose of a leader node and a compute node? How many compute nodes can there be for a leader node and what are the maximum sizes?
Leader: manages client connections, parses queries, develops query plans and coordinates parallel execution for compute nodes
Compute: Executes queries, stores data and performs compute operations and sends intermediate results to leader node.
1 Leader: 128 Compute Nodes. Max size of 160GB
In RedShift, how do the EVEN, KEY and ALL distributions distribute data over the compute nodes?
Even: Rows are distributed evenly across all nodes
Key: Rows are distributed according to the values of a column. Leader node attempts to place all rows with the value on the same compute node
All: Copy of the entire table is place on each node. Use only for slow moving tables that are not updated often.
When restoring a redshift database, do you need to wait for the restore to complete before you can start querying it?
No. Redshift restores into a new cluster and that cluster is available immediately for use before all data has been restored.
In redshift, is encryption enabled by default for data at rest or in transit? If not, can it be enabled and when?
No. You must enable this at creation. If you havn’t and need encryption you need to create a new cluster an migrate the data.
