What does synchronous replication promise a later reader?

• The reader sees the write, because copies were confirmed
• The reader sees older data for speed
• The writer never waits for copies

What is a partition key?

• The password for a database node
• The backup copy of a table
• The value that decides which node holds each row

Asynchronous replication always shows every reader the newest value.

Circle one:   True   False

One seller holds half of all rows. What will you see?

• Every partition runs slightly warm
• Reads get faster everywhere
• One hot partition while others idle

An orders table is keyed by customer. Which query turns slow?

• One customer's orders
• All orders placed last week
• One customer's latest order

A write returns, and a replica read one second later shows the old value. What explains it?

• The partition key was chosen badly
• The copies update asynchronously and lag behind
• The write was never sent

A shop tolerates slightly stale reads but fears one slow node blocking every sale. Which pairing fits?

• Key by a rare query with synchronous copies
• Keep no copies at all for maximum speed
• Key by buyer with asynchronous copies

A team keys its orders table by order date yet mostly looks up single customers. What is the mistake?

• The key serves rare reports while punishing daily lookups
• Dates cannot be used as keys
• Customer lookups need no key at all