Scaling Reads easy
What is the main downside of reading from a Read Replica instead of the Primary database?
- A Replicas are slower hardware.
- B Replicas do not support SQL.
- C Replication Lag: The data on the replica might be slightly outdated compared to the Primary.
- D You need a special password.
Answer: C. Replication Lag: The data on the replica might be slightly outdated compared to the Primary.
It takes a non-zero amount of time for data to travel from Primary to Replica. During this window, a user might write to Primary and then immediately read from Replica, getting old data (Stale Read).
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