PROFESSIONAL-CLOUD-ARCHITECT · Question #324
You work for a multinational company and are migrating an Oracle database to a multi-region Spanner cluster. You have to plan the migration activities and the DBAs have told you that the migration wil
The correct answer is B. You have to change most of the primary keys. With traditional SQL databases, it is advisable to use numerical primary keys in sequence. Oracle DB, for example, has an object type that creates progressive values, called a sequence. Instead, it is important that distributed databases do not use progressive keys, because the t
Question
Options
- AYou need to drop the secondary indexes
- BYou have to change most of the primary keys
- CYou need to manage table partitions
- DYou have to change the schema design of many tables
How the community answered
(23 responses)- A13% (3)
- B57% (13)
- C26% (6)
- D4% (1)
Explanation
With traditional SQL databases, it is advisable to use numerical primary keys in sequence. Oracle DB, for example, has an object type that creates progressive values, called a sequence. Instead, it is important that distributed databases do not use progressive keys, because the tables are split among the nodes in primary key order and therefore all the inserts would take place only at one point, degrading performance. This problem is called hotspotting. A is wrong because Spanner handles secondary indexes. C is wrong because Spanner automatically manages the distribution of data in the clusters. D is wrong because we already know that the structuring of the tables follows the standards.
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