Databases · Middle · Question 10 of 75

Why can random UUIDs (v4) as primary keys slow down inserts on large tables?

1UUIDs can't be indexed
2UUIDs need a separate table
✓Correct answer: New keys land on random index pages, causing more page splits and cache misses than sequential keys

Explanation

Time-ordered IDs (UUID v7, ULID or bigint identity) append to the end of the index, keeping the hot part small and in memory.

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