Oracle MySQL 5.7 Database Administrator — Question 2

You have a consistent InnoDB backup created with mysqldump, the largest table is 50 GB in size.
You start to restore your backup with this command;
shell> mysql –u root –p < backup.sql
After 30 minutes, you notice that the rate of restore seems to have slowed down. No other processes or external factors are affecting server performance.
Which is the most likely explanation for this slowdown?

Answer options

• A. The MySQL server has stopped inserting data to check index consistency.
• B. InnoDB is doing CRC32 checks over the tablespace data as it grows.
• C. The MySQL server is taking a periodical snapshot of data so it can resume the restore if it is interrupted mid-way.
• D. InnoDB has filled the redo log and now must flush the pages.
• E. Secondary indexes no longer fit into the buffer pool.

Correct answer: A

Explanation

The correct answer is A because when the MySQL server checks index consistency, it can temporarily halt data insertion, causing a slowdown in the restore process. Other options like B, C, D, and E describe situations that do not typically lead to a slowdown under the described conditions, as they either relate to different processes or would not specifically cause the observed behavior.