フリー問題

問題文

A telecommunications team's VACUUM job on a huge table is slow, and they add 8 more workers. Nothing improves. What is the likely reason?

選択肢

1. The retention threshold is too long, so more files must be examined during the listing phase; shortening it lets the workers finish the listing faster. The driver size does not need to change.
2. VACUUM does not use workers at all, so worker count never matters.
3. The slowdown is in the phase where the driver issues delete commands, which is a driver-only operation, so increasing the driver size is the appropriate response.
4. The table has too many clustering keys, which slows the file listing phase, so the number of keys should be reduced before adding more workers.